I need to remove the black from CMYK images for electronic test scanning. How can I remove the K from a CMYK image and keep the darks as close as possible to the original.

. . . you could try Selective Color, move to the Black channel and move the slider to the left and then compensate by moving the other color sliders to the right until you get a 'balance' of what your looking for.

You can use the Channel Mixer to do cnk's suggestion with more control. In the past I used the color settings to go from rgb to cmy (without k) but I can not get it to work in the new color management settings. I remember it was something one had to set to default to not change images to black-less ones... An internet search on PS cmy did not bring a lot of hits either, but I learned a log of inkjet printers use the cmy model. Doing it by hand and saving the channel mixer settings for later reuse might be the best option.

That seems to work. I made an action using the "Way of the Channel Mixer that gets rid of the K. Checked by moving the cursor around the picture and looking at the info pallet. The picture seemed to look a bit washed out so I made a copy of the image and multiplyed it with itself. Image was now too dark so I pulled back the opacity of the top multiplying picture to 50% and that seemed to make it better. Any other thoughts about this. I quess taking out the K leaves an image a bit washed out.

I made an action that seems to do the job. 1. mode> change to cmyk 2. channels mixer output channel to black change black source to -200% for quick and nasty it seems to work alright. I can adjust the colors manualy if the picture looks to washed out.

oh, you may like the ink profile with 0% black then..

this is what a converted black looks like with only one action. (when I tried channels mixer with a some what normal cmyk profile it just went Completely wrong)

before you convert to cmyk try this custom profile...