: InDesign CS4 displays transparent image correctly on screen, but the exported PDF sometimes prints a faint background I am working remotely with a client; deliverable product is supposed to be

@Alves566

I had exactly the same problem with a composite image assembled using XeTeX; very late last night I realised that the probably cause of the problem was that the transparent foreground element was RGB while the background was CMYK. I used Adobe Acrobat to convert the PDF to Photoshop 5 CMYK and the faintly visible transparent square artifact completely disappeared on printing. It also had the beneficial side effect of increasing the perceived colour saturation.

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@Phylliss782

If you see a pale gray background:

This problem often happens when using a layer mask but not a C100-M100-Y100-K100 black to cover your image on the layer mask.

As a result, there will be a very small transparency since not all 4 channels are covered at 100%; some will be covered at 95%, some at 99%, etc. It's very hard to see on screen because it can appear as a very very pale gray, almost white. This is amplified on some printers.

If you used a layer mask, try to change your black to 100% in all the CMYK value or re-do it with that registration black.

It's not the case here, but sometimes using JPG also does this in some editing software like Microsoft Word; the compression can add that kind of effect because of the small pixel distortion.



If you want to verify if this is the issue, you can make a test by flattening your PSD file on a white background, and using the "color picker" on the white area. Look at your info window and see if there is any small percentage of CMYK there. If you see something, that means your transparency isn't fully transparent.





If you see a pale border:

It could be that you didn't remove 1 line of pixels all around on your layer mask or didn't delete it. Sometimes doing a "select all" will still leave that line and it's not always visible because of your gray artboard.

Make sure to select OUTSIDE the frame and add some black on your layer mask in this portion too, all around your image. Or to delete this.





If none of the above are the issue

If you used transparency in InDesign on another background, try rasterizing that image with its background instead or do it in Photoshop.

You won't lose much quality, your client is not using any press but a small office laser or inkjet printer probably. And that's also what's your client is doing when doing a "print as image" in a way.

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