In a monochromatic color scheme, only one hue is used
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The hue is lightened by adding white ti it (tints), darkened by adding black to it (shades), and dulled by adding grey to it (tones).Additionally, pure black and white may be incorporated into a monochromatic color scheme.
Start with finding an image you would like to paint. You will have to adjust it in Photoshop to break it into values and resize it to fit 10"x7.5" board.
1. Find an image. It cannot be a logo or somebody else's artwork. It should be a photograph.

2. Save it to your desktop or your flashdrive.
3. Right-click on it and choose: Open with > Adobe Photoshop

4. Next step is to make the image blacj and white.

Go to the menu bar and choose: Image > Adjustments > Desaturate.

5. Next - let's make it more contrasted.

Image > Adjustments > Auto Levels

6. Let's check the image size:

7. Check "Constrain proportions" so that the picture does not get distorted.. Then, make sure the image is 10 x 7.5 inches. If it is smaller than that - change the document size so that width and hight are equal or slightly bigger than 10" and 7.5"
Click OK

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8. Choose Rectangular Marquee Tool from the Tool box on the left.
In the Options bar: Change style to "Fixed Ratio"
width and hight are 10 and 7.5 (or 7.5 x10 if the picture is vertical).
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9. Drag a selection of the area that you want to paint:

10. Crop the image: Image > Crop

11. Now resize the image to fit exactly on the drawing board:

12. Apply filter:

The image will be opened in a new window:

13. Change the filter settings in the right pane: Levels: 6, Edge Simplicity: 4, Edge Fidelity: 2

Click OK
14. Now print 4 copies!
File > Print
Choose the printer
Copies: 4
Scale: 100%
Check the paper orientation. Then print.

15. Transfer the image onto the board.
16. For this painting, you will mix a "custom color" hue. Combine any two or more hues you want to create your own "custom-color". Make enough paint to be able to complete your painting... you don't want to try to make the same exact color again if you run out.
Premix different values og your color by adding white or black to it. Match you custom color values with greys in the image.
17. The darkest shapes in your reference image will be painted the darkest value or black. The lightest shapes will be painted the lightest level or white.

More examples:
 
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