Duotone ... how?

[Dario]

Hi all!

This is not strictly 'color management' but...
The other day I faced an issue while my press man colleague was printing a B&W image - the issue was I remembered that in the old days (20 years ago, on 2 color presses) I/we used to create a custom duotone from B&W images using Photoshop, and then to print ... I don't remember how!!
Do you recall something about this?
How to properly set up a duotone to print B&W photos??
I know the technicality to do it in Photoshop, but I don't remember the proper way to get a nice print from two inks - which inks, BTW? Black and...?

Thanks!

 

[SteveSuffRIT]

No special rules, based on personal preferences.
2nd color duotone needs 30' degree angle angle rotation so no more pattern.
K always at 45' and should have normal tone reproduction (TR) for highlights (H) and mid-tones (M), and shadows (S).
The 2nd color has flatter curve in H and steeper in S to add more density, color, contrast.
If you use a brown-orange for 2nd color, then it looks like an old "Sepia" tone photo.

 

[gregbatch]

In the old days we had a binder from Pantone filled with samples of various spot color combinations, including a screen matrix and a duotone.

 

[Dario]

screen matrix

what's that? (sorry - my bad English)

 

[Repro_Pro]

Google "Pantone color and black selector".
That guide was mainly useful for choosing a desirable combination of 2 screen tints.

 

[Dario]

Google "Pantone color and black selector".
That guide was mainly useful for choosing a desirable combination of 2 screen tints.

these were really old days!!

 

[Ulrich]

all about the curves is said already above, but i just want to add the opportunity of using two times Black for duotone to get maximum contrast and preventing color shifting instead of K and as a second colour grey, it depends from the sujet. We once had produced a comic with nearly "bitmap"-drawings, adding a second (Pantone-) black just above 90% tone-value in grayscale for an example, the result was darker than tint.

 

[Repro_Pro]

This may be obvious to many, but I think it should be mentioned:
Photoshop has an Image Mode"Duotone" offering selection and viewing of the results with any additional spot color.
This may certainly help in evaluating different options.