I wish I figured this out on my own, but I found it on a U-tube video by Jason Morgan (JasonMorgan.co.uk). He’s a wildlife artist. This particular video is titled “Painting Tips – Preparing a photo for the underpainting stage.” You may want to view it after reading how to prepare the photo.
When a reference photo has a lot of detail, like a picture of a tiger, for instance, it is difficult to look beyond the detail for what the colors underneath should be.There is an easy PhotoShop process to help you out.
Open your reference photo in PhotoShop. This photo is from WildlifeReferencePhotos.com.
Go to the menu bar and open up “Filter.”
Then open up the Filter Gallery. Your photo will be on the left and if it is too big, look at the bottom of the screen and you’ll see you can adjust the size down. The two filters that work the best for this are “Paint Daubs” and “Palette Knife” in the Artistic Filter Gallery.
Play around with the stroke size and detail until you can see that the detail has been smoothed out to show areas of color. Don’t worry about the whiskers because they get painted in last anyway.
The adjusted photo is on the left and you can see the underpainting colors easily. But there is one more thing to do. Because the detail gets painted on top of these colors, it needs to be darkened for the underpainting. Go to “Image” and change the brightness by moving the bar to the left until it is a little bit darker. For more specific information on the brightness/contrast tool, go to “Finished Artwork: Brightness and Contrast.”
Now when you paint the details, like the hair, on top of the underpainting, they will be the right color and stand out beautifully.
