Device N- Why???

[prepress cindy]

For a quick summary of my nightmare, I am solely responsible for prepping 150 magazines a month for print, about half are B&W. The ad design and magazine layout are done by college kids with limited knowledge to put it nicely. Also there are a lot of ads that come supplied, so god knows who are setting up those. When I first started a few months ago I was having nonstop issues with transparencies and white overprints. Posting on this site helped me change the InDesign settings under output to the following:
Color conversion: Covert to destination (preserve #'s)
Destination: Document CMYK (SWOP)
Profile Inclusion: Don't include profiles
This has worked beautifully! No more transparency issues and I can now use Pitstop to correct all white overprints. But the issue that has finally been brought to my attention is that all the grayscale images are being converted to device n and are printing in CMYK. I did some reading this weekend and come to the conclusion it has something to do with my InDesign settings, but what and which one I don't know. What bothers me the most is when you look at the PDF in acrobat all images are on the black separation only, so how would I have even known? I have to right click on each image and go to the color tab and look at the color space. Pleas help!

 

[Stephen Marsh]

What workflow/RIP is converting your K only Device-N images to CMYK (I presume that there is unwanted CMY data)? It sounds like the problem is with your workflow/RIP and not the file.

One could setup an automated conversion to convert only the grayscale/devicen raster images to a K only channel CMYK file, however that would be bloating the file with 3 extra channels. In my opinion it would be preferable to get the Workflow or RIP working correctly.

http://printplanet.com/forums/color-management/25021-converting-cmyk-iso-coated-grayscale-offset
http://printplanet.com/forums/attac...ted-grayscale-offset-converttok_isocoated.zip


Stephen Marsh

 

[prepress cindy]

The files come to me as a PDF using the setting I noted above, I bring them back into InDesign using a plugin provided by HP to prepare them for HP Indigo digital presses. I thought device n is CMYK, is it not? I cannot have them "force" (don't know if thats an option) to print only black because the cover is full color.

 

[Al Ferrari]

If you are bringing the customer full file pdf back into InDesign for re output, then one option (perhaps not the best one) would be to re output the full color cover as a separate pdf from the grayscale pages, and put them back together down stream.

Al

 

[gordo]

I thought device n is CMYK, is it not?

I don't know in your specific case but device n usually means spot colors I.e. colors or separations beyond cmyk

Gordo

 

[Greg_Firestone]

Hi Cindy,

Do you have a sample file you could provide for us to play with (so we can see the device-n) as well as your PDF job options? I think it might make sense to revisit your PDF settings. The new settings you mentioned shouldn't effect transparency. My feeling is that the color conversion is where your problems are stemming and could be changed without impacting transparency.

Greg

 

[Greg_Firestone]

I don't know in your specific case but device n usually means spot colors I.e. colors or separations beyond cmyk

Gordo

Device-N can also be multi-tone elements (e.g. Cyan+Yellow, Black+Magenta+Cyan). Some apps will automatically convert an CMYK element to Device-N if it determines it doesn't need all 4 plates.

Greg

 

[prepress cindy]

I just heard from back from my offset printer. I was wondering if it was coming out CMYK on their end and its not. So now I'm thinking its an HP Indigo thing where its interpreting the device n as cmyk.
Greg you mention that my new setting should not affect transparency, they did before in the old settings of:
Color conversion: no color conversion
Destination: na
Profile Inclusion: include all profiles
that was full of issues and Pitstop did not detect overprints.

 

[Greg_Firestone]

I just heard from back from my offset printer. I was wondering if it was coming out CMYK on their end and its not. So now I'm thinking its an HP Indigo thing where its interpreting the device n as cmyk.
Greg you mention that my new setting should not affect transparency, they did before in the old settings of:
Color conversion: no color conversion
Destination: na
Profile Inclusion: include all profiles
that was full of issues and Pitstop did not detect overprints.

Hi Cindy,

Glad to hear the files do not have added CMY in the Grayscale images. My comment regarding transparency was that unless you had a RGB blending space, color conversion isn't necessary for transparency flattening. I have heard of issues with white overprinting from transparency flattening and it boggles my mind that it does it. I'm sure there is a technical reason why it's done, but it makes no sense to me. I'd be curious if you still get the Device-N when you flatten transparency with your old settings.

Your Indigo RIP should be able to handle Device-N; it's been around since PDF 1.3.

Regards,
Greg

 

[prepress cindy]

What is the setting in InDesign that takes a grayscale photo and changes it to device n?

 

[Joe Duffy]

What is the setting in InDesign that takes a grayscale photo and changes it to device n?

Confused - you stated this:
prepress cindy
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I just heard from back from my offset printer. I was wondering if it was coming out CMYK on their end and its not. So now I'm thinking its an HP Indigo thing where its interpreting the device n as cmyk.

and now you wonder where InDesign is converting to Device N? I thought it was the HP RIP that was doing this?

If you are making a CMYK file and a image is tagged Greyscale, not Black, would the RIP not make it a Device N - as a 5th color? Seem to remember this happening in PitStop

 

[prepress cindy]

It is InDesign that is making a grayscale image device n. The offset rip is leaving it as black only and the Indigo is turning it into CMYK. If I open the grayscale image in Photoshop and view it in Acrobat it only shows data on the black plate. So Im left with trying to figure out how to change the Indigo (good luck to me) or changing a setting in InDesign.

 

[Joe Duffy]

What does PitStop say it is?
Try this, create a pdf from a 4c tiff and convert it to Greyscale in photoshop, save as a pdf and send to the HP - is it CMYK?.
Open it in PitStop and see if both that one and the one from InDesign are both colored the same.

 

[Greg_Firestone]

It is InDesign that is making a grayscale image device n. The offset rip is leaving it as black only and the Indigo is turning it into CMYK. If I open the grayscale image in Photoshop and view it in Acrobat it only shows data on the black plate. So Im left with trying to figure out how to change the Indigo (good luck to me) or changing a setting in InDesign.

Hi Cindy,

If you turn off Color Conversion in the PDF job option, it won't convert the grayscale images to Device-N. I know you want to keep this on because of your other issues, but this is the setting which is converting the grayscale images to Device-N.

Greg

 

[prepress cindy]

So I changed the setting to no color conversion and don't include profile (because include all profiles still gave me device n) and now its grayscale. So thats just great, now I have to choose between grayscale coming out correctly or transparencies? Why is nothing easy!

 

[Joe Duffy]

If you have PitStop server or PitStop, you can have a action that allows you the TX you desire and then convert the photos you need to greyscale.

 

[prepress cindy]

I have used Pitstop to convert the images and its comes out horrible! Totally washed out looking. That would be an easy fix but I have seen other posting with people voicing the same complaint. I have also tried doing the grayscale conversion using Acrobat convert colors but for some reason that causes an error with the Indigo press setup plug in.

 

[michaelejahn]

This is the key bit of detail that stands out ( to me anyway )

"I bring them back into InDesign using a plugin provided by HP to prepare them for HP Indigo digital presses."

So, 1st and foremost - why would you need a Plug-in from HP to place a PDF file into an Adobe InDesign document ? What is that HP Plug-in actually doing for you ? What happens if you DONT use that Plug-in ?

Related to "deviceN" - should NOT be any issue UNLESS there is some color conversion being forced onto an image - the fact is, that some CMYK images can be represented using only 265 different colors - an example might be a picture of a lemon or an orange against white - so your CMYK images are no longer 8 bits per channel within that PDF - BUT - a well behaved RIP will know how to make color separations ( or - in the case of the HP Indigo ) - it will re-separate that into the colors that is required.

 

[rich apollo]

What is the setting in InDesign that takes a grayscale photo and changes it to device n?

device-n isn't really an issue. It can be device-n and still be a single channel image falling on the black plate - for all intents and purposes, grayscale.

The HP plug-in you're using, is it Smart Stream? Is this for variable data or for imposition?

Are you going out JLYT or PDF? They output differently and I haven't found any solid controls on JLYT preferences.

How is the workflow set up on the Indigo? It sounds like you're converting there.

I have some grayscale (supposedly) items that I deal with monthly, and I settled on converting them with an Acrobat Preflight Profile (as a droplet). Acrobat allows you to convert into a grayscale colorspace - InDesign doesn't. I tend to deal with color anywhere but InDesign. It's gotten better, but it's so oddly configured (and the nomenclature is so unique) that I stay away. Acrobat gives you access to more explicit color controls. You stated that you were unhappy with the results using PitStop. Did you review the color management preferences? PitStop has to be configured to work reasonably with color. The default color settings are terrible.

 

[buckeye]

Rich,

Could you provide a snapshot of your PitStop color management preferences? Our preferences are set to the default color settings and I was curious as to what your settings are for a color managed shop - as yours seems to be.

Thanks in advance,

Erik