Ok. Here's a quick review of the process I showed today on how I monitor and correct my values in digital painting.
1. Make sure you are working all on one layer.
2.Create a duplicate of that layer.
3. Create a new layer and fill it with a medium gray value. Set that layers blend mode to "Color."
- This will give you a more accurate depiction of what your values are than just desaturating the image or using an adjustment layer, because it takes into account the value of saturated color.
4. Combine the gray layer and one of your duplicated layers. You should now have a layer with your painting in grayscale above a layer with your image in color.
5. Paint in gray scale on the gray scale layer until your values look right and are reading clearly. Remember value grouping!!
6. Once the you have the values as you want them, make sure that you once again have one gray scale image on top of the original color image (in case you added any layers in step 5). Now set the gray layers blend mode to "Luminosity." This will make all the color underneath it match the values in the Luminosity layer.
7. Combine the two layers. You should now again have one layer with your image, now with the value adjustments. You might need to make some slight color adjustments in the areas where you changed the value, but make sure not to change the value. I recommend setting the color pallet to "HSB" and using that to pick colors.
8. Rinse and repeat. I find my self going through this process at frequent intervals when painting to make sure I'm where I want to be.
9. Sit back and admire your beautiful work. Way to be.
Hope this helps! Sorry no screen shots. If you have any questions let me know.