Hello curious stranger ^_^ I'm guessing your here to learn how to colour in a horse eye, well you're in luck! Come come, sit down, tea or coffee? I shall teach you the little that I know.
In total I used 4 layers; (from top to bottom) eyelashes, shine, outline, and colour
(note: this tutorial will not show you how to draw the eye)
1. Draw the eye (outline), then colour in the eye (colour) from here on out we will be using alpha lock until we get to the shine and eyelashes. Here I tend to use a bright, bold colour so that missing spots are easy to catch.
2. Colour in the Nictitating membrane (third eyelid). I tend to use grey-brown for brown scale horses and grey for grey scale horses. The membrane tends to be glossy so to bring out the folds, add shine lines, the bottom, furthest from the eye should be the darkest part. Also, figure out your base colour (what colour you want the eye to have/be).
3. Here we begin shading ^^ once you have found your base colour, use the darkest colour off of its scale and fill in the eye. From there, grade up, lowering the brush size every time. The first two shades should circle the eye, then begin to cut off the circle at the top, each time making the gap bigger and bigger. Stop at one- fourth of the way on the colour chart in the bottom left corner. You don't want the eye to become "too bright".
4. Use the blender tool and sort of make spikes toward the middle of the iris (pulling the dark into the bright). Do Not try to blend! You will loose those glorious spikes. Do not over spike, unless you want a boring, dull eye. It takes practice so don't worry if you can't get it at first, Rome wasn't built in one day.
5. Now we do radial lines. Remember dark at the top then grade down to bright. On a side note, keep the lines equally spaced and the brightest line should be as bright as the brightest part of the eye.
6. Add the Sclera. Keep the iris oval with the pupil and veins are commonly seen in the sclera. I would stay away from white when colouring in the sclera. Instead use creme and or light brown colours. Veins should be dark redish- brown, bold reds will make the horse look fake and diseased.
7. Choose a dark shade of the colour of the iris and draw lines in as shown. The goal is to make these lines barely noticeable and slightly blended. Do not blend in the lines, you will ruin the entire eye if you do. Simply lower the opacity it roughly 20%, then draw in the lines. Second, grey off the bottom part of the pupil.
8. On the separate layer, add glare. Glare has to be the most difficult thing to master, It also takes a great amount of practice. How I remember and base my glare, I use the simple rule that the sky is bright and the ground is not.
9. Lastly, add the eye lashes. I used a think brush and followed the back part of the eyelid line. Then I used the finger tool and spiked the line like how we did in step 4. The eye lashes' eye should be a dark shade of the horse's coat colour.
Fin~
Have fun colouring and may the odds be ever in your favor ^_^
Feel free to ask if you have any questions!