TryingToCreate

Hello all. Thanks in advance for your help. OK, so I have Photoshop CS2, and I am trying to take a picture and make it all one color. What I am looking for here is to make the picture all shades of yellow. I have looked all over the net for days now and can't seem to find anything to help me with this. Is there some way to only use yellow?

I find this frustrating because the software I used before this had the option to pick what colors you used in a picture. So basically I could select only yellow and then the whole thing would go yellow. I tried the replace color thing but it is too confusing. Also, it does not replace white. I need help.

MindBender

Image > Mode > Grayscale
then
Image > Mode > Duotone

From the duotone menu you can control the exact colors you want to work with.

If this isn't destined as a spot printed document, and you just want the effect of a duotone, then you can achieve the look and feel of it with a gradient map or gradient map adjustment layer, although it will still be a RGB document.

Welcome to PSG.

Gaussian

Welcome TryingToCreate [righton]

I don't know if this is what you're looking for, if not then maybe you find it useful for other purposes.
The same can be done with a Hue & Saturation adjustment layer (colorize option selected), but I prefer Solid Color because it's easier to select the proper color and the color will also be visible in your layers palette.

Use Mindbender's suggestion if you're interested in multiple colors or if you prefer his method in general, I'm just suggesting alternatives.