2 colors & transparancy blend space

[zap]

I'm workink on a book of 2 colors job (1-spot,2-the program's black), wich transparancy blend space I have to work on:RGB/CMYK. That's project is itented for commercial printing (PRESS).
THANKS!
Is there's a problem with combinations of such colors & transparancy & overprint, & also a accurate preview for press.
I know I can use the color mixer for colors combinations, but I want to use transparancy features also: shadows, feather, multiply and else....should I have problems on the output?

[AdobeAce]

Hi Zap,

Always use CMYK for PRESS, never RGB.

As far as Transparency and Spot Colors, applying most Color Modes is not a problem, BUT using some Modes such as DIFFERENCE, EXCLUSION, HUE, SATURATION, COLOR, or LUMINOSITY can lead to some very unexpected results that are totally different that what's on your screen. So take care.

Make sure to check your layout using Overprint Preview to get a better idea of what might happen when printing.

Effects such Drop Shadows and Feather shouldn't be a problem.

For more infomation, check your InDesign Help menu (Help > InDesign Help and do a search for "Best practices when creating transparency.") Also make sure to check with your printer. Printers know better than anyone how to deal Transparency issues.

[GuyB]

Two other things I might add :
1- using transparency, it is a very good idea to always put your type on the topmost layer of your doc;
2- besides the Overprint Preview, suggested by AdobeAce, you can also have a good idea of what your doc will lood like, mainly with transparency, in the Flattener Preview (Window/Output Preview/Flattener Preview). You can find all you need to know on this in the Help.

[DCurry]

Also, use the Separations Preview (it comes up in the same palette as the Flattener Preview.) You'll be able to turn off your Black and Spot plates, and see if anything remains on the page. If it does, then it is not going to separate properly onto one of those 2 plates.

[dmalph]

Be wary of placing a drop shadow over a PMS color in InDesign
( I'm assuming you are working in InDesign). I've had problems with
this before where a white box will show up behind your drop shadow.
A fix: Make a Pantone black be your second color and serve as your drop shadow color also.

Another thing I've learned is to use Acrobat 7 Pro to flight check
your documents. Export as a PDFX-1a through InDesign, and
your resulting PDF will show any printing problem you will have.
Acrobat 7's flight check program is even more detailed than
Flight Check is, and much more advanced than InDesign's built in
version, and though it is very detailed, will show you any problems
with your file.