Text in Photoshop.What about overprint ?

Let's suppose we have a cmyk document in photoshop with a text layer - text is vector not rasterized - with 100% K text, over a background image and we intend to send the file for offset printing, as pdf.

I have read an article about setting the mode of the text layer to "multiply" and not to "normal" if we want to make black text overprint.

Is this ok? Sounds practical but I would like your opinion about it. If not, is there any other tested way to control the overprint procedure?

Thanks in advance.
Themistoklis Chapsis.

Multiply will indeed cause overprinting. This can be tested by opening the PDF in Acrobat Professional and turning on the separations preview.

For best results, save as PSD first, then save as PDF without layers, but with text and vectors retained.

Bob

Thanks a lot bob !

It works as explained. Nevertheless it's a surprising result. PhS help says:

'The blending mode specified in the options bar controls how pixels in the image are affected by a painting or editing tool. It's helpful to think in terms of the following colors when visualizing a blending mode's effect:
The base color is the original color in the image.
The blend color is the color being applied with the painting or editing tool.
The result color is the color resulting from the blend.
To select a blending mode for a tool:
Choose from the Mode pop-up menu in the options bar.
....
Multiply
Looks at the color information in each channel and multiplies the base color by the blend color.
The result color is always a darker color. Multiplying any color with black produces black. Multiplying any color with white leaves the color unchanged. When you're painting
with a color other than black or white, successive strokes with a painting tool produce progressively darker colors. The effect is similar to drawing on the image with multiple magic markers.'

Interpreting this help text literally would mean IMO:
The resulting color in all channels would be 'as dark as possible'. This is R=G=B=0 or C=Y=M=K=100 (because it's
applied to ALL channels).

In fact I had expected 'inverse knockout' which means:
instead of knocked out white we get black 100% C,M,Y,K.

But it works correctly for separations - black text is on the K-plate and the other plates are not affected.

Best regards --Gernot Hoffmann

There is nothing better, than a confirmation from dear Gernot ! Thank you very much !

Dear Themistoklis,

I thought your question was really interesting,
and I had checked everything immediately (like Bob).

Thanks for the positive feedback.

Best regards ---Gernot Hoffmann