[Laura]

Techie question ^_^

I have been exporting some imagery to an online printers' and I have come across the problem of exporting my colour image with text into a PDF (simples, Photoshop does this for you) after converting to CMYK and making my blacks 100%.

I have never wholly understood the entire process of how to go about sorting out my blacks to 100% in Photoshop so I am hoping someone could explain to me?

Thanks!

[wyldflowa]

http://www.bittbox.com/all/photoshop...rue-black-cmyk

Eyedropper tool something that's supposed to be "black" on your picture and look on the palette and see if it's got the following values - C-75 M-68 Y-67 K-90. If not, you can either tinker about with an adjustment layer or do it the lazy way if your picture is aliased - use select>colour range and eyedropper the black on your image, slide the fuzziness around so it selects the bits you want true black then flood fill the area selected with the C-75 M-68 Y-67 K-90 black on a new layer.

If your picture is anti-aliased then it would produce a nicer effect if you just recoloured the black bits with true black. (lock the layers then recolour them true black with the pen tool)

That's how I'd make them true black though I haven't done it before and can't guide you on saving to pdf either! ^^;

[yakumo]

I used to work at a printer. The idea is that just 100% black ink isn't quite a thick enough layer to cover the whiteness of the paper. It'll actually look more like a dark shade of grey.
When a document is printed in CMYK, you can use the other three colours (cyan, magenta and yellow) to get a darker black: When these three inks are combined they form a dark brown colour, on top of which the black ink is printed. The combined result is a very dark black, which is what you want.

There is a 'perfect ratio' for that mix of colours, which is pretty much as wyldflowa mentions. Converting an RGB image to CMYK in photoshop usually does this correctly, automatically.
If it doesn't, the image below shows a quick way how to (after converting to CMYK mode)
When you save to pdf, just make sure you keep CMYK in the colour conversion thingy, something as shown.

[KimShibbyBob]

I also used to work for a litho printer, we used to change blacks to C40 M40 Y40 K100, although having the CMY elements as low as 20% is OK.

[Karasu no Kazu]

This is very interesting and something I hadn't thought about before! I shall be using the advice in this thread when I prepare my colour work in future.

And that just sounded like a spam post. Ah well!