How to blend colors in Photoshop like paint?

Is there a way to set up a photoshop file so that when you paint colors over eachother, they automatically blend as if they were pigments? i.e. when you paint a yellow line over a red line, the result is orange where they overlap?

Or is Photoshop not the right type of program for this?

Thanks everyone - however, not exactly what I was looking for. I'm not looking to blend and smudge colors together to "mix" them like paint, I'm looking for a setting so that when you paint a pure yellow line over a pure red line, the result is that the lines are orange where they overlap (to understand what I mean by "overlap", think of a Venn diagram).

I think the issue is that you physically do not get orange when you overlap pure red R:255 G:0 B:0 and pure yellow R:255 G:255 B:0, since there isn't any orange in either color to start with (thus no orange left over when the colors are blended subtractively).

Let me know if I've got that right.

10 Answers

Don't forget to checkout the other options for the smudge tool.

Like any other brush. You can adjust diameter and hardness.

You can also adjust strength and enable the nifty finger painting mode...

Photoshop CS5 introduces the bristle tipped brushes and the mixer brush tool to get some really cool 'real' paint brush effects. See for an example.

Set up two layers.

On layer 1, paint your red.

On layer 2, paint your yellow.

Then, while layer 2 is active, on the layer properties panel, set the dropdown from "Normal" (the default) to "Overlay". That should get you the blending mode you're looking for. The area where the two overlap will be orange - a (more or less) 50/50 color blend between the two layers.

For certain "pigment colors" simply using multiply works. Pure cyan, magenta and yellow will blend as expected. For other colors you need to do some trickery.

To expand on what was said in an earlier post: To get a yellow/red blend you need to use the Normal blend mode at 50%, the issue is that it will make the entirety of the top blend layer uniformly 50% transparent. To address this you need to create a layer sandwich.

For example:

Yellow: R:255 G:255 B:0 Alpha: 50%

Red: R: 255 G:0 B:O Alpha: 100%

Yellow: R: 255 G:255 B:O Alpha: 100%

This will net you an orange at the intersection, but both venn fields will be 100%

Unfortunately this is not uniform across all expected color blends. Especially a blue + yellow make green type of situation (it makes gray mud). A way to FAKE this is to use color or hue overlays of the expected color over the mix area.

The same is true for illustrator, which would actually be easier for venn diagrams due to its pathfinder tools. You could simply do a merge or divide of overlapping shapes and then recolor the intersecting areas. This is still manual, but gives you greater freedom.

Set the opacity of the brush lower or try to change the mode next to it to something that fits your need.

In CS5 (and I do believe that in earlier versions as-well) you can set the brush mode.
Usually 'screen' or 'lighten' would get what you want.
You'd have to experiment with it a bit, sometimes with different colors or contrast you'd need a different mode to get the desired effect.

I was looking for a solution and resolved this mystery myself. Change your document mode to CMYK instead of RGB. Now you will be working with channels, instead of layers, to blend colors in Photoshop like paint.

Build up some value on the magenta channel. Then build up a heavier value on the yellow channel. The result will be orange. A nice pumpkin orange is a blend of 50% magenta and 100% yellow… That is, paint middle gray on the magenta channel and pure black on the yellow.

Make one brush mode: Linear Dodge (Add) and then paint the line over the other, it should sort of "blend", it might give you the effect you're looking for.

I think this is the final answer to this topic:

Use one layer for each color and set each layer as Linear Dodge (Add). Use normal brush.

Change the opacity and the flow of the brush to 75%... some overlapping and mixing will occur. Digital artists use that method together with blending with eyedropper, smudge and mixer brush to get mixes and transitions. Since you explained that you just wanna get overlapping mixes try it. Also consider using the multiply layer mode.