Posts Tagged ‘GIMP’

Turn your action sequence shots into a film strip

Sunday, May 29th, 2011

Use GIMP to turn photos into film slides and then join them together into a film strip.

That's the future Usain Bolt doing the 100m sprint

That's the future Usain Bolt doing the 100m sprint

The most straightforward way of conveying recording motion is to shoot video. However, photos can also be used to convey a sense of motion.

One way is to use a fast shuttle speed to freeze motion. Usually the posture of a sprinting man or the midair position of a mountain bike tells a story someone or something in motion frozen in that split second of exposure.

The other way is to do a panning shot. The photographer uses a relatively slower shuttle speed and moves camera such that the moving subject is kept at within the same location in the viewfinder. This is much trickier but the results can be dramatic. Only the moving subject is in focus while the surrounding background is blurred in motion blur. This effect can sometimes be simulated using a photo editor.

Yet another way is to shoot a sequence of photos of the moving subject. The photos in the sequence show the moving subject at various stages of movement. Many compact cameras today feature a burst mode for shooting action. Once the camera is focused on the moving subject, press down the shuttle release button and hold it down. The camera shoots in rapid succession a series of shots of the moving subject.

Combining the sequence into a film strip

Last week, we saw how the Slide filter in GIMP can modify a digital photo to make it look as if it is mounted onto a film slide.

To make a film strip, simply apply the Slide filter separately to each photo in the sequence, and then join them together into a single film strip. Photos in landscape orientation will result in a horizontal film strip while photos in portrait orientation will result in a vertical film strip.

Use the Slide filter in GIMP to turn each photo into a film slide Use the Slide filter in GIMP to turn each photo into a film slide Use the Slide filter in GIMP to turn each photo into a film slide

Use the Slide filter in GIMP to turn each photo into a film slide

Below are a few points to note while combining the slides into a strip:

All the photos in the sequence should be of the same size, so that they can be joined together seamlessly.

When the Slide filter is applied to a photo, the resulting photo that with the slide frame comprises three layers: the original photo (cropped to 3:2 aspect ratio), the slide frame  (with the sprocket holes and the text labels), and a coloured background (which shows through the, the sprocket holes of the slide frame).

Sequence of photos taken in burst mode using a Sony SLT-A55V
Sequence of photos taken in burst mode using a Sony SLT-A55V
Sequence of photos taken in burst mode using a Sony SLT-A55V

Sequence of photos taken in burst mode using a Sony SLT-A55V

Use the Image > Flatten Image command from the main menu to flatten the layers into a single layer to make it easier to drag and transfer it to another image window.

After each of the film slides have been flattened, drag and drop each of them the image window containing one of the film slides. This will become the workspace for joining the separate film slides into a single film strip.

Select the  Image > Canvas Size command from the main menu. A “Set Image Canvas Size” dialog box pops up.  First click the chain link between the Width and Height text fields so that one value can be changed independently of the other. If the film strip is to be horizontal, increase the Width, if the film strip is to be vertical, increase the Height.

To save the trouble of doing manual calculations, change the units in the dropdown box from “pixels” to “percent”. Then change the Width or Height field to the appropriate multiple: if there are to be two photos in the film strip, increase from 100 to 200 percent; if there are to be three photos, increase to 300 percent. Press the “Resize” button to confirm the change.

The image window shows only one of the film slides, the others are hidden directly below it. Select the Move Tool in the Toolbox. Drag the top film slide to move it. Hold down the Ctrl key on the keyboard while dragging to constrain the movement of the film slide to strictly horizontal or vertical movements.

Drag the film slides until they are positioned end-to-end with each other, and forms a horizontal or vertical film strip.

You can use the arrow keys on the keyboard to nudge the film slides so that the edges are seamless and doesn’t show any gaps in between.

Save the file and you have your film strip.

Turn your photo into a film slide

Sunday, May 22nd, 2011

Tired of simple white borders for your digital photos? GIMP has a simple filter that adds a frame around the photo to make it look like it is a film slide – complete with black frame, sprocket holes, and labels.

Turn your digital photo into a film slide using the Slide filter in GIMP.

Turn your digital photo into a film slide using the Slide filter in GIMP.

Adding a border around a digital photo adds visual interest to make it look more interesting, and can focus the viewer’s attention on the main subject as well. If you’re feeling fanciful, you can easily add a decorative border around your photo to turn it into a film slide. Here’s how.

The original photo in landscape orientation. Photo from morguefile.com.

The original photo in landscape orientation. Photo from morguefile.com.

With your photo open in GIMP, select the Filters > Decor > Slide command from the main menu.

The pop-up dialog box for the Slide filter.

The pop-up dialog box for the Slide filter.

The “Slide” dialog box for the filter pops up with various options to customise the appearance of the slide.

The original photo in portrait orientationTurned into film slide

The Slide filter can also be applied to a photo in portrait orientation.

Filter options

The “Text” option allows you to enter a label for the slide. You can use it to caption your photo. Or you could type in “Kodak” to emulate a real slide. For “Number”, type a number from 1 to 37.

The “Font” and “Font color” options lets you specify the font face and colour of the text and numbers adorning the slides of the slide. Leaving them to the default values produces the most realistic results.

Leave the “Work on copy” option checked so that a duplicate copy of the photo will be used for the slide effect and the original is left unchanged. Press the “OK” button and GIMP churns out your slide as a new image which you can save as a JPEG file under a different name.

Points to note

If the original photo is in landscape orientation, the black frames with sprocket holes and labels will be added to the top and bottom sides of the photo. If the original photo is in portrait orientation, the frames will be added to the left and right sides.

Original photo is too close-cropped

The colour of the sprocket holes will be based on the current background colour in the colour swatches in the Toolbox. So if you want the holes to be white, remember to reset the background colour to white by pressing “D” on the keyboard, before applying the filter.

If the aspect ratio of the photo is anything other than 3:2, it will be cropped into that ratio. If you want to control exactly how the photo is to be cropped, crop it yourself to 3:2 first before applying the filter. This will ensure you don’t end up with half a face being cropped out of the photo.

Letting the filter crop to 3:2 aspect ratio may have a blinding effect

Letting the filter crop to 3:2 aspect ratio may have a blinding effect.

Use the crop tool to do your own cropping to crop it exactly the way you want it.

Use the crop tool to do your own cropping to crop it exactly the way you want it.

Going down nostalgia lane

Tuesday, May 17th, 2011
Did you see the front page of The Sunday Times on 15 May? The portraits of MM Lee and SM Lee were splashed across half the front page in sepia – that faded brown tint that adds a sense of nostalgia to photos because of the association of that toning effect with photographic print techniques from a bygone era.

Lee Kuan Yew (photo from BBC) Lee Kuan Yew - in sepia tone

Old Photo filter in GIMP applied with Defocus and Sepia options selected but without Mottle nor faded border effect.

Minister Mentor Lee Kuan Yew and Senior Minister Goh Chok Tong are two former Prime Ministers of Singapore who had tendered their resignations on Saturday, May 14 to quit the Cabinet – in order to make way for a clean slate for the current Prime Minister Lee Hsien Loong to reform the ruling PAP government.

Goh Chok Tong (photo from BBC) Goh Chok Tong - in sepia tone

Old Photo filter in GIMP applied with Defocus, Sepia and Mottle options selected together with faded border effect.

The first and second Prime Ministers of the island nation, both brought Singapore from a fledgling, newly-independent, former-colonial state barely able to survive – to the modern nation it is today. Despite handing over their Prime Ministership to their successors, both had been actively involved in the government.

So it was surprising to see, so soon and suddenly, both their portraits published in sepia – suggesting they have become part of a bygone era.

Sepia toning

 

Select the Filters > Decor > Old Photo command from the main menu

Select the Filters > Decor > Old Photo command from the main menu

“Beginning in the 1880s, sepia was produced by adding a pigment, called sepia, made from the Sepia officinalis cuttlefish found in the English channel,to the positive print of a photograph,” according to Wikipedia. The specialized treatment gave the photograph a warmer tone and enhanced the archival qualities of the prints.

Simulating a sepia effect in GIMP

It is easy to simulate a sepia effect to a digital photo using photo-editing software.

In GIMP, open the digital photo to be modified and select the Filters > Decor > Old Photo command from the main menu. The “Old Photo” dialog box pops up with options to control how the photo is to be “aged”.

The Old Photo filter comes with options to age the look of a photo.

The Old Photo filter comes with options to age the look of a photo.

You can “Defocus” the photo to make it slightly blur, add a faded white border, apply a “Sepia” tone, or “Mottle” the photo to simulate the blobs of pigment you see in old photos. Checking the “Sepia” checkbox will tell GIMP to desaturate the image, reduce brightness and contrast, and modify the color balance to apply the sepia effect.

Once you click “OK”, GIMP gets to work on the photo.

If you just want to get a black-and-white version of the photo, or tint in a different colour from sepia, or want more control over how the final result looks like, check out the  “Black-and-white and Sepia” tutorial that was part of the 14-part Basic GIMP Series of tutorials.

Using Curves to enhance brightness and contrast in GIMP (Final Part 14 of 14)

Sunday, May 15th, 2011
Both the rudimentary Brightness-Contrast command and the handy Levels command allows you to enhance the tonal balance of a photo and for correcting colour balance. But the Curves command gives you ultimate control over how specific tones are to be tweaked in your digital photo.

The Levels command allows the user to adjust the three main tonal ranges of a photo – the shadows, midtones and highlights. The Curves tool, however, allows you to target any tone or tonal range in the photo to tweak their brightness and contrast.

Using the Curves command

With the photo open in GIMP, choose the Colors > Curves command (or Tools > Color Tools > Curves)  from the main menu. An “Adjust Color Curves” dialog box pops up showing a square grid with a straight diagonal line. The histogram of the photo can be seen in the background of the grid for reference.

As for the Levels command, an understanding and analysis of the histogram of the photo is the basis for using the Curves command.

The horizontal X-axis of the grid represents the initial brightness values – from zero (black) to 255 (white) – of the pixels in the photo before the Curves command is applied. The vertical Y-axis represents the brightness values that each pixel is to be mapped into after the adjustments have been applied. It also ranges from zero to 255.

The lower left corner of the grid represents the black point (for pixels with brightness value zero) while the upper right corner represents the white point (for pixels with the maximum brightness value of 255).

Adjusting brightness

To begin adjusting the photo, click anywhere on the diagonal line in the grid. An anchor point is added to the line. You can drag the anchor point around with the mouse.

Drag the point downwards to make the photo darker. The straight diagonal line turns into a curve passing through the anchor point and the black and white points. A faint straight diagonal line is still visible in the grid – it serves as reference for an unadjusted photo.

When the cursor is inside the grid, you can see the X (input) and Y (output) values of the cursor at the top left hand corner of the grid. Mouse-over the anchor point that you’ve just dragged. In the example, you can see that the brightness of any pixel with original value 128 (X-value) will be reduced to 160 (Y-value). Pixels with brightness close to 128 will also be darkened. You can eyeball the effects of the adjustments by looking at the photo itself in the image window.

To lighten the photo, drag the anchor point down below the faint diagonal guide. Now pixels with brightness 128 will be darkened to 90, while the pixels of similar brightness will be darkened as well.

To remove an anchor point, simply drag it off the side of the grid. You can add as many as 14 anchor points (excluding the original black and white points) to the curve. This allows you to target up to 16 specific brightness values in the photo for brightening or darkening. However, you seldom need more than a handful anchor points to get the job done.

Adjusting contrast

If the histogram is bunched up the towards the middle, drag the black or points inwards horizontally to where the histogram begins and ends respectively. This is similar to dragging the black and white points of the Levels command inwards to maximise the tonal range of the photo.

The steeper gradient of the line indicates that the contrast of the photo is increased.

A typical Curves adjustment that can be applied to most photos is the “S-Curve”. This curve tends to enhance most photos by increasing the overall contrast and making the photo “pop” with vivid shadows and highlights.

To apply an “S-Curve” adjustment, add two points on the Curve – the first to lower the brightness of pixels of brightness 64, the second to increase the brightness of pixels of brightness 192. The above numbers are just guides – drag the adjustment points around with the mouse while eyeballing the photo.

The S-Curve suppresses the shadows and highlights while increasing the contrast of the mid-tones, where the main subject usually is. Add a third point with brightness of roughly 128 to increase or decrease the brightness of the midtones.

In addition to these adjustment points, you can add additional adjustment points to tweak specific tones in the photo – such as skin tones.

With some practice, you will be able to control and enhance any particular tone that appears in your photo.

Final installement of Intermediate GIMP series

Sunday, May 8th, 2011

The final installment of the 14-part Intermediate GIMP series will be run next weekend.

After more than a week of following the Singapore General Election 2011 and staying up past 3 am to watch the results, I’m afraid I’ve had to postpone the final installment of the Intermediate GIMP series till next weekend.

It will be on using the advanced Curves command to correct/enhance the brightness and contrast of a photo.

Using Levels to enhance brightness and contrast in GIMP (Part 13 of 14)

Sunday, May 1st, 2011
The Levels command is the tool of choice for more advanced users of photo editors for enhancing the tonal balance of a photo and for correcting colour balance.

That’s because it offers better control than the rudimentary Brightness-Contrast command and produces much better results.
The port of Marseilles in Southern France on an overcast evening.

Pict 1: The port of Marseilles in Southern France on an overcast evening.

The overall contrast and brightness has been increased with the Levels command.

Pict 2: The overall contrast and brightness has been increased with the Levels command.

Most free and basic photo editors offer a basic Brightness/Contrast command that allows the user to easily adjust the brightness and contrast of a photo. GIMP tool also has the equivalent in the Colors > Brightness-Contrast command from the main menu.

This basic adjustment command uses a rudimentary algorithm that treats all pixels equally and adjusts them to the same extent. It’s useful if all you need is a quick and dirty adjustment to the photo.

For almost the same effort, the Levels command provides better control and the algorithm yields better results adjusting pixels to different extents depending on the settings you make.

That is why for many free photo editors, more advanced tools like the Levels and Curves command are not available or are only available when you upgrade to a paid version. In GIMP, these tools available for free.

Using the Levels command

This photo of a hanging potted plant is slightly underexposed because the camera has been fooled by the bright background.

Pict 3: This photo of a hanging potted plant is slightly underexposed because the camera has been fooled by the bright background.

The red petals are now more vibrant and discernible after the photo has been enhanced with the Levels command in GIMP.

Pict 4: The red petals are now more vibrant and discernible after the photo has been enhanced with the Levels command in GIMP.

Last week, we looked at how to analyse a photo’s characteristics and problems by examining its histogram in GIMP.

Using the histogram as a basis, we’ll learn to use the Levels command to improve the tonal distribution of a photo such that the overall brightness and contrast of the photo is just right and the entire range of brightness values (from 0 to 255) available is fully utilised.

With the photo open in GIMP, choose the Colors > Levels command from the main menu. A complicated looking Levels dialog box pops up showing a histogram of the photo as well as many controls and input fields to control the histogram is to be adjusted.

The reason why many beginners hesitate to use the Levels command is the seeming complexity of the dialog box. But in most cases, all you need is to drag one to three of the triangular sliders directly below the histogram. Here’s how.

Darkening a photo

Busy bee working on Lavender flowers in Provence, France.

Pict 5: Busy bee working on Lavender flowers in Provence, south of France.

Photo darkened using the Levels command in GIMP.

Pict 6: The photo after darkening using the Levels command in GIMP.

For the slightly overexposed photo of the lavender flowers, the histogram shows that none of the brightness values below 60 is utilised. Drag the blackpoint triangular slider from the left edge inwards towards the right until it is at the point where the main bulk of the histogram starts to form (see Pictures 5 to 7).
Drag the triangular blackpoint slider from the left edge inwards towards the right.

Pict 7: Drag the triangular slider from the left edge inwards towards the right.

The three boxes below the histogram shows the numeric brightness values of where the sliders are. It serves as a reference or when you need to key in specific numeric values to use. Most of the time, you should simply drag the slider inwards based on where the bulk of the histogram begins.

Dragging the blackpoint slider to 60 tells GIMP to darken pixels of brightness 60 and below down to zero. The other pixels in the histogram are correspondingly darkened as well. This also increases the overall contrast of the photo because a wider range of brightness value is now used in the photo.

To further finetune the brightness of the photo, drag the centre slider to the left or right to lighten or darken the mid-tones.

Lightening a photo

Drag the triangular blackpoint slider from the right edge inwards towards the left.

Pict 8: Drag the triangular slider from the right edge inwards towards the left.

For the slightly underexposed photo of the potted flower on the wall, the histogram stops short at around the brightness level 210. Drag the whitepoint triangular slider from the right edge inwards towards the left until it is at the point where the main bulk of the histogram ends (see Pictures 3, 4 and 8 ).

Dragging the whitepoint slider to 210 tells GIMP to set 210 as the white point – all pixels that are of brightness 210 and greater are increased to the maximum of 255. The other pixels are correspondingly lightened as well.

As before, the overall contrast of the photo is increased because the entire range of brightness values is now used in the photo.

Again, drag the centre slider to the left or right to lighten or darken the mid-tones further.

Adjusting all three sliders

The snapshot of the port of Marseilles was taken on an overcast evening and is not only too dark but sorely lacking in contrast, resulting in a dull and flat photo (See Pictures 1 & 2).

The histogram is now spread across the entire range of brightness.

Pict 10: The histogram is now spread across the entire range of brightness.

The histogram in the Levels dialog box shows that all the pixels are bunched up in the mid-tones – there are now extreme white or black pixels – so the highlights are not bright enough while the shadows are not dark enough.

Drag the blackpoint and whitepoint triangular sliders from both edges inwards.

Pict 9: Drag the blackpoint and whitepoint triangular sliders from both edges inwards.

In this case, drag the blackpoint and whitepoint sliders inwards to where the bulk of the histogram begins and ends (see Picture 9). This darkens the shadows and lightens the highlights forcing the bunched up histogram to spread out across the entire range of brightness – thereby increasing the overall contrast of the photo.

As the photo is still too dark, drag the centre slider to the left to further brighten the photo.

The resulting histogram after the adjustment is now spread out across the entire brightness range (see Picture 10).

Understanding histograms (Part 12 of 14)

Saturday, April 23rd, 2011
The histogram of a photograph tells you whether a photo is too bright, too dark or too flat and lacking in contrast.

It forms the basis of more advanced and powerful tools – such as Levels and Curves –  to enhance the brightness and contrast of a photo.
Metalwork lantern in French Provence. The exposure was reasonably well-balanced.

Pict 1: Metalwork lantern in French Provence. Exposure was well-balanced, as indicated by the histogram below.

Many digital cameras today can display histograms on their LCD screens in both the review and preview modes. The histogram helps the photographer to assess whether the exposure settings for an image are optimal. This is most useful when bright sunlight makes it difficult to judge – just by viewing the photo preview/review on the LCD screen – whether a photo is too bright or dark.

If the histogram indicates that the photo is too dark or bright, the photographer can adjust the exposure settings to get a better shot.

Different parts of a histogram. The photo is well-exposed.

Pict 2: Different parts of a histogram. The photo of the metal work lantern was well-exposed.

What is a histogram?

The histogram is basically a graph of the brightness levels of all the pixels in a photograph – from pure black (brightness value zero) on the left edge to pure white (brightness value 255) on the right edge.

An overexposed photo has its histogram bunched up to the right.

Pict 4: An overexposed photo has its histogram bunched up to the right.

Lavenders in the French Riviera - overexposed.

Pict 3: Lavenders in the French Riviera - overexposed.

The number of pixels in each of the 256 levels of brightness are counted and plotted on the Y axis as a bar chart to provide an idea of the tonal distribution of a photograph and its possible problems.

The region around the left edge of the histogram represents the shadows (dark tones) in the photo while the pixels near the right edge represents the highlights (bright tones). The middle region represents the midtones.

Analysing a histogram

When a photo is opened in GIMP, you can view the photo’s histogram by selecting the Windows > Dockable Dialogs > Histogram command from the main menu. By analysing the histogram, you can better decide how to use the tools in GIMP to enhance a photo’s brightness and contrast.

Flowers at Gourdon - underexposed.

Pict 5: Flowers at Gourdon - underexposed.

Port of Marseille on a dull and overcast day.

Pict 6: Port of Marseille on a dull and overcast day.

All bunched up in the middle - poor contrast.

Pict 7: All bunched up in the middle - suggesting a photo with poor contrast.

A well-exposed photo usually has a histogram which looks like a bell-shape and which stretches from one end of the histogram to the other (see Pictures 1 & 2).

A photo that is overexposed (too bright) usually has a histogram that is bunched up on the right, while an underexposed photo will have a histogram that’s bunched up to the left (see Pictures 3 to 5).

A photo with poor contrast will usually have a histogram that is squashed up towards the middle. The photo appears dull and flat. The brightest pixels are not bright enough while the darkest pixels are not dark enough (see Pictures 6 & 7).

Exceptions

Note that there are exceptions under special photographic situations. For example, a photo that comprises mainly bright tones (such a scene comprising white snow against a light coloured sky) can have a histogram that is bunched up to the right, even though it is properly exposed (see Pictures 8 & 10).

Eagle perched atop Gourdon.

Pict 8: Eagle perched atop Gourdon.

Stained glass window in Provencal church.

Pict 9: Stained glass window in Provencal church.

Similarly, a photo consisting of predominantly dark tones can have a histogram that is bunched up on the left – even when properly exposed (see Pictures 9 & 11).
 Bunching up to the right caused by bright background behind the eagle despite proper exposure.

Pict 10: Bunching up to the right caused by bright background behind the eagle despite proper exposure.

Stained glass window in Provencal church.

Pict 11: Histogram is bunched up because of the predominance of dark tones - despite proper exposure.

In the next  installment, we’ll use the Levels command to enhance a photo’s brightness andcontrast based on the characteristics of its histogram.

Designing a poster in GIMP (Part 11 of 14)

Saturday, April 16th, 2011
Layers and layer masks are what differentiates a powerful image editor like GIMP from a basic photo editor. Design a poster for your living room from your favourite photo.
Make a poster or postcard from your favourite photo.

Make a poster or postcard from your favourite photo.

Ever wanted to make a postcard or a poster from your favourite photo? Here are some techniques using layers and layer masks in GIMP.

Add a grid of white dots

Open the photo in GIMP. From the Layers dialog, you can see it resides in the Background layer which is the only layer for the moment.

The original photo from morguefile.com.

The original photo from morguefile.com.

A grid of white dots is overlaid onto the photo.

A grid of white dots is overlaid onto the photo.

Add a new layer by clicking the icon at the bottom left corner of the Layers dialog. In the “New Layer” dialog box that pops up, select the radio button for “White” option under Layer Fill Type and press the OK button.

A new empty layer filled with white is added above the original photo in the Background layer.

Right-click on its thumbnail in the Layers dialog and select “Add Layer Mask” command from the pop-up menu. In the “Add Layer Mask” dialog box that pops up, select the “White (full opacity)” option and press the OK button. A layer mask filled with white is added to the layer – you can see its thumbnail beside the original thumbnail in the Layers dialog.

Use the Grid filter to create the grid of white dots.

Use the Grid filter to create the grid of white dots.

From the main menu, select the “Filters > Render > Pattern > Grid” command. In the Grid dialog box that pops up, increase the horizontal width setting until the preview in the dialog box shows a grid of white dots of the desired size. Here I used a setting of 13.

The white layer now appears as a grid of white dots overlaid on the original photo.

Right-click on the upper layer in the Layers dialog and select “Apply Layer Mask” to merge the layer mask into the original solid white layer. The layer mask is removed and the layer becomes a transparent layer with a grid of white dots overlaid on the photo below.

Hiding the white dots from the heads and faces

Use a layer mask to hide the white dots from the heads and faces.

Use a layer mask to hide the white dots from the heads.

Add a new layer mask on this layer, again selecting the “White (full opacity)” option in the  “Add Layer Mask” pop-up dialog box.

Press “D” on the keyboard to reset the Foreground colour to black. Activate the Paintbrush Tool from the Toolbox and paint on the layer mask in the image window. Paint around the heads and faces of the wedding couple to hide the white dots in that area.

From the main menu, select the “Layer > New from Visible” command to create a new layer that combines all the visible layers in one layer.

Adding the green arc

In the Layers dialog, click to select the layer below the new combined layer. This is so that any new layers created will be added BELOW the combined layer.

Zoom out until the photo is smaller than the image window.

Zoom out until the photo is smaller than the image window.

Set the Foreground colour to green (or your preferred colour). Add a new layer by clicking the icon at the bottom left corner of the Layers dialog. In the “New Layer” dialog box that pops up, select the radio button for “Foreground color” option under Layer Fill Type and press the OK button.

A new layer filled with green is added just below the combined layer.

Right-click the combined layer in the Layers dialog to add a layer mask to the layer, using the “White (full opacity)” option. Press the minus key (“-”) on the keyboard to zoom out the view in the image window.

As the photo becomes smaller than the image window, you will see white space between the edges of the photo and the edges of the image window.

Adding a green arc at the bottom of the poster.

Adding a green arc at the bottom of the poster.

Activate the Ellipse Select Tool from the Toolbox and drag an elliptical selection around the couple’s heads. You can begin dragging in the white space between the photo and the edge of the image window so that the elliptical selection covers most of the photo except for a small arc at the bottom of the photo.

Remember you can adjust the size and position of the elliptical selection by dragging the side or corner control handles of the selection outline. Once happy with the selection, use the “Select > Invert” command from the main menu to invert the selection.

Press “D” on the keyboard to reset the Foreground colour to black. Select the “Edit > Fill with FG Color” command to fill the arc with black (in the layer mask).

An arc of green is revealed below the photo.

Adding the white highlight

Click on the green layer in the Layers dialog to select it.

Add a white highlight band in the green arc.

Add a white highlight band in the green arc.

Add another new layer, this time selecting the radio button for “White” option under Layer Fill Type. The new white layer is added above the green layer but below the combined layer.

Add a layer mask to the white layer, selecting the “Black (full transparency)” option in the pop-up dialog box. A layer mask filled with black is added to the layer.

Press “D” to reset the Background colour to white. Using the Rectangle Select Tool from the Toolbox, select a vertical band and use the “Edit > Fill with BG Color” command from the main menu. A white band is added to the layer mask such that a white band runs through the green arc.

Adding the text captions

GIMP's Layers dialog.

GIMP's Layers dialog.

Click the combined layer (the topmost layer) in the Layers dialog to select it, so that any text captions added will be added above it.

Activate the Text Tool from the Toolbox. In the Tool Options below the Toolbox, set the font, size and colour settings for the Text Tool. Click in the white band in the arc with the cursor and type the word “Wedding”. Click in the green portion to add the word “Kiss”.

After adding the captions, you can still change the font, size and colour setting for these captions by selecting them first with the Text Tool and then modifying them in the Tool Options.

Add edge shadow

Add a new empty layer right at the top of all other layers. Activate the Blend Tool from the Toolbox. Press “D” to reset the Foreground colour to black and the gradient to “FG to Transparent”.

Again, zoom out the photo (by pressing the minus key on the keyboard) until the photo is smaller than the image window. Drag a black-to-transparent gradient from outside the right edge of the photo (but inside the right edge of the image window) to slightly inside the right edge of the photo.

Save the file in .xcf format so that you can come back to tweak the design in the future. Save as .jpg to send the file for print at the studio.

Compositing your photos in GIMP (Part 10 of 14)

Saturday, April 9th, 2011
Composite various photos into a collage by making them merge seamlessly together – using Layers and Layer Masks in GIMP. Today, we’ll try a simple fading effect and merge two photos int0 each other.
Composite two photos seamlessly together using GIMP.

Composite two photos seamlessly together using GIMP.

Now that you have learnt about Layers and Layer Masks, there are many tasks and effects that you can do using them. I had some questions from readers about how to apply certain effects to their photos so that they can use them in their websites.

Morning dew on flowers at our hotel in Provence, France

Morning dew on flowers outside our hotel in Provence, France

Fading to white allows captions to be added.

Fading to white allows captions to be added.

They’d seen these simple effects being done on other websites and would like to find out how they’re accomplished. In these two parts, we’ll try some that involve compositing a few photos together.

Fading a photo to white (or any other colour)

This is easy. After opening the photo in GIMP, activate the BlendTool in the Toolbox.

The Blend, Move and Paintbrush tools are in the Toolbox.

The Blend, Move and Paintbrush tools are in the Toolbox.

In the Tool Options below the Toolbox, click on the rectangle beside the “Gradient” label and from the dropdown list of options, select “FG to Transparent” gradient.

Click on the Foreground Swatch in the Toolbox and select white from the “Change Foreground Color” dialog box that pops up. If you want the photo to fade to black, red or any other colour instead of white, simply select that colour and set that as the Foreground colour.

Now move the cursor to the image window and drag it from the left side of the photo to the right. A gradient going from pure white to nothing is overlaid onto the photo so that it appears as if the photo is fading into white. If you are not satisfied with the fading, press Ctrl-Z to undo and try dragging again. Trial and error is the best way to get your ideal fading effect.

To fade in more gradually, drag further. You can of course drag from right to left or drag vertically or diagonally – depending on how you want the fading effect to appear.

The disadvantage of this quick-and-dirty method is that the gradient is added directly onto the photo. Once you’ve saved and closed the file, you can’t adjust the fading effect to reveal more of the original photo anymore.

Applying the gradient on a separate layer

Here’s a non-destructive approach that allows the fading effect to be tweaked six months down the line.

Instead of applying the gradient directly to the photo in the Background layer, apply it to a new empty layer above the Background layer. This way, none of the pixels in the original photo in the Background layer is changed or “destroyed”. The fading effect can be changed anytime in the future by replacing or modifying the colour and gradient in the upper layer.

Here are the steps.

Apply the gradient to an empty layer above the photo.

Apply the gradient to an empty layer above the photo.

Add a new layer by clicking the icon at the bottom left corner of the Layers dialog. In the “New Layer” dialog box that pops up, select the radio button for “Transparency” option under Layer Fill Type and press the OK button.

A new empty layer is added above the original photo in the Background layer.

Use the Blend Tool to add the gradient to the new empty layer.

The result is that the photo appears to fade into white. You can further finetune the overall effect by using the Move Tool from the Toolbox to move either the photo in the Background layer or the gradient in the upper layer.

Simply activate the Move Tool from the Toolbox, click to select the layer you want to move in the Layers dialog, and drag in the image layer to make the move. You may find it easier to first change the default option of the Move Tool to “Move the active layer” to better control which layer you want to move.

Merging two photos into each other (non-destructively)

Little house on the prairie? More like ruins in a field of lavender.

Little house on the prairie? More like ruins in a field of lavender.

This intelligent Spaniel named Bugis lives on the lavender fields of the Valensole plateau.

This intelligent Spaniel named Bugis lives on the lavender fields of the Valensole plateau.

Pleasant memories from our drive through Valensole in Provence

Pleasant memories from our drive through Valensole in Provence

To merge two photos into each other, simply place one photo as a layer above the other photo. Add a layer mask to the upper layer and use the Blend Tool to apply a gradient to the layer mask. The two photos will appear to blend into each other.

Here are the steps.

Open the first photo in GIMP. The photo resides in the Background layer which is the only layer in the Layers dialog for the moment. Bring in the second photo as a new and separate layer by using the “File > Open as Layers” command from the main menu. The new layer sits above the first photo in the Background layer.

Right-click the image thumbnail for the upper layer in the Layers dialog. In the pop-up menu, select “Add Layer Mask”. In the Add Layer Mask dialog box that pops up, press the Add button – any of the options in the dialog box for initialising the layer mask is fine since we will be modifying the layer mask immediately after creating it.

Press “D” on the keyboard to reset the foreground and background colours to black and white respectively.

Activate the Blend Tool from the Toolbox using any of the three “FG to BG” gradients in the Tool Options. Because the layer mask is active, dragging the Blend Tool in the image window will add the gradient to the layer mask instead of the white layer itself. The layer mask hides part of the photo in the upper layer based on the gradient in the layer mask. The result is that the two photos appear to fade into each other.

Again, none of the pixels in the two photos are altered or “destroyed”. The fading effect can be changed anytime in the future by modifying the gradient in the layer mask of the top layer.

I've modified the layer mask by painting with the Paintbrush Tool.

I've modified the layer mask by painting with the Paintbrush Tool.

You can further modify the blending by using the Paintbrush Tool from the Toolbox to paint either black or white into the layer mask. Remember – white reveals the pixels in the upper layer while black hides. Shades of gray makes the pixels in the upper layer translucent.

As before, you can also use the Move Tool to move either of the photos around.

Digitally apply a graduated ND filter to your landscape photos using GIMP (Part 9 of 14)

Sunday, April 3rd, 2011

Instead of paying to buy a graduated neutral density filter and go through the hassle of carrying it around and fitting and unfitting it everytime you use it, simulate the effect using layers and layer masks in GIMP.

When taking photos of sceneries where the bright sky occupies the upper half and the foreground occupies the lower half, it can be difficult to capture the entire range of brightness levels to show the details clearly.

The park within the grounds of Nijojo Castle in Kyoto.

The park within the grounds of Nijojo Castle in Kyoto in autumn.

The sky has been darkened and the foreground lightened.

The sky has been darkened and the foreground lightened in GIMP.

The clouds and the sky can be too bright; while the mountains, trees and houses in the foreground may be too dark. This is made worse under the harsh sunlight of the midday sun when contrast in the photo will be at the highest.

The traditional way to get around this, is to avoid the midday sun, or to buy a graduated neutral density (ND) filter – if you own an SLR that allows filters to be attached to the lens.

The graduated ND filter darkens the upper portion of a photo so that the sky will not be overexposed while a brighter exposure can be used for the whole photo such that the foreground will not be too dark.

What if you use a compact camera, on which typically you can’t attach any filters? Or you find it a hassle to attach and unattach filters between snapshots? Or you simply don’t want to pay for another camera accessory that you have to carry around?

Using layers and layer masks in GIMP, you can pretty much simulate the effect of a graduated ND filter on the computer.

Simulate a graduated ND filter digitally using GIMP

I snapped the autumn colours of the park within Nijojo Castle in Kyoto from the top of the castle keep. The clear blue sky was rather bright while trees along the moat in the foreground of the photo were too dark.

Darkening the photo to darken the sky would make the foreground too dark. Brightening the photo to brighten up the foreground would overexpose the sky.

Duplicate two copies of the original photo in the Layers dialog.

Duplicate two copies of the original photo in the Layers dialog.

To control which areas to darken and brighten, first duplicate the original background layer twice by clicking twice on the Duplicate icon at the bottom of the Layers dialog.

Two new layers containing copies of the original photo are now created above the background layer. We will darken the upper copy and lighten the lower copy and then use a layer mask to merge the two layers so that only the darkened sky and the brightened foreground is visible.

Brightening the foreground

First hide the upper copy by clicking the eye icon to the left of its thumbnail in the Layers dialog.

Drag the middle slider directly below the histogram.

Drag the middle slider directly below the histogram.

Now click on the lower copy by clicking on it in the Layers dialog. Brighten the lower copy. You can use Colors > Brightness-Contrast I generally prefer the Colors > Levels command. I will cover this command in more detail later in the series.

In the Levels dialog box that pops up, look below the Input Levels histogram and drag the middle slider to the left until the foreground is suitably lightened. You can see the entire photo lighten as you drag the slider.

Pay attention to the foreground and ignore the sky which will become excessively bright. You can see the numeric value of the middle slider in the centre text box just below the histogram. I used a setting of 1.35

Darkening the sky

Select the upper copy in the Layers dialog by clicking on it. Turn its visibility back on by clicking on the where eye icon previously was.

The lower duplicate copy is lightened with the Levels command.

The lower duplicate copy is lightened with the Levels command.

The upper duplicate copy is darkened to make the sky more dramatic.

The upper duplicate copy is darkened to make the sky more dramatic.

Darken this layer using the Colors > Levels command.

In the Levels dialog box that pops up, drag the middle slider to the right until the sky is suitably darkened. Again, pay attention to the sky and ignore the foreground which will become excessively dark. I used a setting of 0.45.

Blending the two copies using a layer mask

Select the White (full opacity) option.

Select the White (full opacity) option.

Right-click the upper copy and choose Add Layer Mask command from the pop-up menu. Click the radio button for “White (full opacity)” option and click on the Add button.

A layer mask is now added to the upper copy. In the Layers dialog, you can see the thumbnail for the layer mask to the right of the image thumbnail in the layer containing the upper copy.

Activate the Blend Tool from the Toolbox. Reset the colour swatches in the Toolbox by pressing “D” on the keyboard. In the tool options below the Toolbox, make sure the “FG to BG” Gradient is selected.

Activate the Blend Tool from the Toolbox.

Activate the Blend Tool from the Toolbox.

Here’s the magic, click the cursor somewhere near the top of the yellow tree and drag the mouse vertically upwards until the cursor is just above the clouds in the sky before releasing the mouse button.

A black to white gradient is painted into the layer mask for the upper copy. The white parts represents the parts where the upper copy will be visible and the black areas represents the parts where the upper copy will be hidden. Grey areas represents areas where the upper copy is partially visible.

Where the upper copy is hidden or translucent, the lower copy will show through. The result is that the darkened sky of the upper copy will be visible while the lightened foreground of the lower copy will show through.

The layer mask shows the darkened sky and the lightened foreground.

The layer mask shows the darkened sky and the lightened foreground.

By painting in the layer mask with the Paintbrush Tool with black or white, you can further finetune exactly which parts of the darkened upper copy to remain visible and which parts of the lower lightened copy to show through.

You can further tweak the final result by adjusting the opacity of the two copies by dragging the layer opacity sliders for each of the layers. The layer opacity slider is found at the top of the Layers dialog.

You now have a pseudo-HDR (High Dynamic Range) photo which captures both the lightest tones in the sky and the darkest details in the foreground in a single photo.