This GIMP (GNU) tutorial demonstrates how to resurface eyeballs with the aid of a non destructive Mask Layer. To work along, you are welcome to download the Brown Eye and Barcode Start Images I am working with Here. Unzip the file and open the Start Images onto GIMP’s workspace.
Eraser Tool Blending Versus Mask Layer Blending
With care, you are able to produce the same blend using the Eraser Tool, however, the Eraser Tool lacks the sophistication, accuracy and control of Mask Layers. For example, once you have removed pixels using the Eraser Tool, they cannot be retrieved easily. With a Mask Layer, erased pixels can be painted back at any time: and as long as you save your work as a GIMP XCF File, removed pixels can be painted back even after the image has been closed and reopened. Blend Images Using The Eraser Tool Tutorial Here.
You can quickly Undo a step at any time by pressing Ctrl then Z. Alternatively, click a previous Undo History snapshot - Windows then Dockable Dialogues then click Undo History. In addition, to Zoom in (or Zoom out) of your image; from the top menu, choose View then select a Zoom Tool from the subsequent drop-down list.
Create A Fill Layer
Understand Blend Modes
Launch GIMP & Organise Its Workspace & Palettes
Ensure the Layers and the Undo History Palettes are visible, and then drag them into position over your workspace - (Windows then Dockable Dialogues - then click Layers and Undo History).
If you are utilising your own Start Images, you must resize them so they are approximately the same size.
This is an introduction to Layer Mask Blending, and to keep things simple I am working with two photographs; however, you can blend as many images as you wish. Additionally, all New Layers can be converted to a Mask Layer.
An Introduction To Masking - Click Here!
1/ Lesson - Create A Photographic Cat And Merge
To open the two Start Images onto GIMP’s workspace; from Gimp’s top menu, choose File then Open - Ctrl then O. Now, from the Open Image dialogue box, navigate to the folder where your Start Images reside, then Ctrl-click to highlight both files - and then click Open.
Now, from the Brown Eye Image’s Top Menu, choose Edit and then choose Copy.
Then from the Barcode’s Top Menu, choose Edit and then choose Paste as and then choose New Layer - as illustrated below.
The Brown Eye Image will now be Pasted onto the Barcode Image - as illustrated below.
It’s safe to Close the original Brown Eye Image - top menu, then File then Close.
To create a Layer Mask, you must have more than one Layer in the Layers Palette.
4/ Add A Layer Mask
Now, right-click over the Brown Eye Image’s Layer, and from the subsequent drop-down list, select Add Layer Mask.
And from the subsequent Add Layer Mask dialogue box, accept the following default White (Full Opacity) setting, and then click Add.
After clicking the Add tab; a Mask Layer will then be added to the Brown Eye Layer - and the Layer’s appearance will change to the following. The White Rectangle (highlighted in red below) indicates the Mask Layer.
Layer Mask (Rectangle) Note
Whilst editing the Brown Eye Image, the Mask Layer must remain active at all times. If needed, you can reactivate the Layer Mask by left-clicking over White Rectangle (Layer Mask Thumbnail).
Now, tap your Keyboard’s D Key. This sets the Foreground Colour Swatch to Pure Black and the Background Colour Swatch to Pure White - as illustrated below.
(Alternatively, click the following tiny black and white swatch).
To paint with Mask Layers, you must set the Foreground Colour Swatch to Black.
If necessary, click the following Switch Foreground and Background Colours (double arrows tab) - or press your X Key to swap the Colour Swatches around.
When painting with Mask, remember, painting with Black removes pixels and Painting with White brings them back.
You will find the next step easier to achieve if you enlarge your image by Zooming into it. (I zoomed in twice).
Bear in mind, when utilising the Zoom Tool, you need to adjust the Paintbrush Tool’s Size according to the amount of Zoom.
Now, from the left-side Toolbox, activate the Paintbrush Tool.
And to start, select a Soft-edged Round Brush; and choose a Brush Size that’s suitable for your photograph’s needs. I am beginning with the following Paintbrush settings; - however, remember, for a perfect blend, you’ll need to change the Brush Size - and its Opacity - as you work.
You can quickly alter the Paintbrush’s Size (Scale) by tapping your Keyboard’s Square Bracket Keys.
Still working on the Mask Layer, (the Brown Eye Layer) - and using the Paintbrush Tool - left-click over your image, and carefully begin to remove the White Eyeball - as illustrated below.
Paintbrush Application Note
You can apply the Paintbrush in one continuous stroke. Alternatively, you can apply it one click at a time.
Step Backwards Note
You can quickly undo a paintbrush application by tapping Ctrl and then Z.
Note - Blending Techniques - Continue with tutorial here
If you reduce the Paintbrush Tool’s Opacity to - for example, 30%: painting will remove less of the White Eyeball Layer - as illustrated below. To create a seamless blend, experimenting with the Opacity level is absolutely paramount.
An alternative way of fading images is by changing the Foreground Colour to (and experimenting with) various shades of grey - as fully explained here.
Additionally, changing the Paintbrush Tool’s Blend Mode can provide interesting and useful results. (Understand Blend Modes).
The Brown Eye Layer’s Mask Thumbnail depicts the removal of the eyeball by displaying a black blotch - as illustrated below.
Now, slowly remove more of the white eyeball - remembering to resize the Paintbrush’s Size - as required. This displays more of the underlying Barcode’s Layer - as illustrated below.
Paint Back Pixels Note
If you get over enthusiastic with your Paintbrush Tool, or it suddenly develops a mind of its own and shoots off at an adverse angle - as illustrated below.
Simply change the Foreground Colour Swatch to Pure White by clicking the following swap arrows: - or tap your X Key.
And then paint over the mistake. Painting with Pure White paints back areas that have been removed.
Alternatively, you can quickly retrace your steps by clicking Ctrl then Z.
Now, ensure the Foreground Colour Swatch is set to Pure Black and continue to remove more white eyeball pixels.
Reposition The Bar Code Image Tip
To reposition the Bar Code Layer: first activate the Barcode Layer.
Now, from the left-side Toolbox, activate the Move Tool.
And then drag the Barcode Image to a position of your liking.
Remember to reactivate the Brown Eye (Mask Layer).
And continue painting with Black - or White, depending on whether you are removing or reapplying the White Eye Ball. Remembering to adjust the Paintbrush’s Size (Scale) and its Opacity as needed.
10/ Perfect Blending
When using Layer Masks, I find the best way to blend transition lines - as highlighted below; is to reduce the Opacity of the Paintbrush Brush, as previously mentioned here.
Additionally, (working on the Top Layer): experiment with different Blend Modes, and discover how they can facilitate perfect blending.
Now, continue changing the Paintbrush’s Size (Scale) and remove - and reapply as necessary, the White Eyeball - until you have removed it completely .
Blur Tool Tip
You can blend the transition line between the White Eyeball and the Barcode using the left-side Toolbox’s Blur Tool: setting a low Blur Rate.
Prior to Flattening the Layers, you may want to save your work as a GIMP XCF File.
After you have completely removed the White Eyeball, (and you are satisfied with your result): from the top menu, choose Image and then choose Flatten Image.
Fill Layer Tip
My Tutorial Here demonstrates how to create a Fill Layer and Fill it with either a Solid Colour, Pattern or a Gradient.
To create extra impact, apply a Sharpening Filter of your choice - Filters then Enhance.
Congratulations, your Resurfaced Eyeball Blend is complete, and it is ready to save.
Now you are familiar with Mask Layers, you can have lots of fun blending photographs. Depending on your choice of images, the process can be quick - or time consuming. The key to success is practise and patience.
Wendi E. M. Scarth. Top of Page.