Hi,

I have the need to convert sets of 4 individual, 2,540 DPI, 1-BIT, prescreened CMYK files (1-Bit TIFFs) into PDF format for inclusion into a standard CTP workflow. This is similar to copydot except that files are not scans of films, they are created digitally. I see on your website that PDF-Robot does not support the use of copydot, though. I need to be able to do this myself on an ongoing basic, so sending the files out to a service bureau would not be a viable option for me. Could you suggest a utility or workaround that would help me achieve this? I’m a graphics professional and used to coaxing programs into doing things that are outside of their normal scope so please do not hesitate to get technical in your response.

Thanks so much for your help!

Hello, Here's a how to method may work, need to test it but should work? Create a Document in Quark 6.5 that is exact size of images. Next, Place first image in a new picture box, same size as quark document. Set Overprint for that box and its image. Then, Duplicate that box by going step & repeat, 1 time, exact coordinates 0, 0. Place next image , each layered, set to overprint, and colorized each tiff with correct color you want to separate to, like C, M, Y, K, Repeat layers of colorized Tiffs tiffs srt to overprint each other till you're done. These are digitally registered. If the images actually register to each other these boxes will maintain that, because of duplicate coordinates, they will register. Now, these are layered, as you place each scan in the 4 windows, be careful to not move cordinates, Save to EPS as Quark 6.5 eps format, DeviceN color space, no bleed, etc. OK, Distill with NO COMPRESSION, NO RESOLUTION CUT , 1 to 1 pixels in/out. Preview the image as a PDF in Adobe Acrobat 6 or Acrobat 7 Professional, Advanced Menu > Output Preview, toggle through the colors look at Advanced Menu > Overprint Preview, look at overprint filter, see if looks right. That would be a good file in the end and easy to create? It's worth testing that out. . . Let us Know if Works & what RIP? HTH

picaBOY,

Thanks for the quick response! I’m really happy I found this forum.

I think your idea worked perfectly.

I followed your directions (very well written!) to the letter. For a test I used a 2,540 square image containing a fine checkerboard pattern. The folder containing my original 1-Bit TIFF test files is 46.2MB, the intermediary EPS file is also 46.2MB, and the final distilled PDF file is 46.5MB. So far so good, it seems.

Then I wanted to check out the results so I rasterized the PDF file back into Photoshop CS (this is where the 1-BIT TIFFs came from to start with). At first everything looked perfect, but upon close inspection it appeared that single rows and columns of pixels from the original files were disappearing.

I tried different versions of Photoshop and got the same basic anomaly, but in different places in the image! I also rasterized the Quark EPS file into Photoshop and it had the same problem, but again, in different areas.

Then, I converted the PDF to a TIFF using Graphic Converter 5.5. When I open that TIFF into Photoshop it looks perfect, every pixel is in place.

I am figuring that this problem is a bug in Photoshop and that the PDF file contains all the correct data. Would you agree?

Thanks again for your help.

picaBOY,

I’ve been working around with variations of your suggestion for a while now, and no matter what I try the 4 colors do not appear to be overprinting (when viewing them onscreen -- I have not tried making plates yet). If I rasterize any type of file (Quark EPS, Quark PDF, or Quark EPS > Distilled PDF) into Photoshop the black pixels of the color that I have in the top picture box in Quark are knocking out of the other 3 colors. The white pixels are acting as clear. It appears the same way when viewing the distilled PDF in Acrobat 6.

Regarding the picture boxes, here’s how I have them set up:

Box color: none
Picture color: set to C M Y or K, respectively
Shade: 100%
Trapping - Picture: Overprint

Interestingly, if I save an EPS out of Quark as a DCS separation, I get 5 files on disk (as expected), and when I rasterize any of the individual color channel files from the DCS group as a grayscale into Photoshop it looks perfect (aside from the missing pixels as mentioned previously.) Though, as soon as I take that EPS file (saved as a 5 file DCS 2 group), distill it, and view it in Acrobat, the colors are not showing up as overprinted. For example, in my test I have the cyan picture box on top. Any black pixels in the cyan 1-Bit TIFF knock out to white pixels in the other 3 colors (at least they do when viewing the distilled PDF in Photoshop, Graphic converter, or Acrobat 6).

I’d hoping that this lack of overprinting is purely a complication with trying to view the PDF files, and that when run through a RIP the correct pixel data for each plate will actually make it to those plates without the rip trying to knock colors out of each other.

Any thoughts?

Thanks

Hi Satori, welcome to the group man. Long time member, first time post, welcome and nice idea by the way. OK, with respect to the overprinting of these final files. You cannot really count on the rip into Photoshop as a verifier, it may if it's Adobe Photoshop 7, not sure, I'm just saying I don't think that verifies either way. Adobe Acrobat Professional is the way to verify that it's correct.

Now if you are in Acrobat 6 or 7, you can see the overprints using overprint preview, but other than that, it will look like a layer, only the top visible. Remember, these are not transparent images, so until separated, there is actually no overprint. In Adobe Acrobat 6, or 7 Professional, be sure to check Advanced Menu > Overprint Preview , then use Advanced Menu > Separation preview as you switch off the colors on top, you will see if the layer underneath will be knocked out or not.

So, whether you have these files that will actually do what you want mechanically, the files will not show all 4 colors in display for sure. These files will be a sort of bastard file. But, that's OK, doesn't mean they wont work fine mechanically. I've used all kinds of stuff like this in early days of CTP. That DCS out of Quark is probably the best chance. Then, when you distill, this MUST BE set in the distiller settings to honor the overprints.

One of the things you have to remember about hacking around these 1-Bit TIFF test files is that once they are ripped and screened files, these at 2540, they can only be output on a device that's 2540, 1 to 1, or you'll get moir'e artifacts in the output. These are just like a copydot scan. So, if you needed to output these on a 2400 dpi device, you're looking at some serious re-sampling. Only GOOD tool for that is Creo's CopyDot Toolkit .

What rip are you sending these through? I can see these working fine through a Harlequin Rip as a composite file, but I'd predict them to have problems through a Creo Scitex Brisque RIP. If you send them through a Scitex Brisque, probably want to take that Quark DCS, then output pre-separated postscript into the Brisque. Because of the Scitex CT & LW format and RIP paradigm, it's going to have a hard time with this file as a composite workflow. Remember at anytime they go through a Distiller they can easily get resampled and lose the overprints. These files can work but will always have special handling and care to stay ontop of.
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