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 a printable PDF.
The problem: The design has a colored background, and over this, an image with transparency. On screen and on my home printer, everything looks perfect. However when my client prints it out, she reports that the transparency isn't right and that a faint box (background) around the image is showing up. This happened for her on two different printers. It's not fully white or solid, just lighter than it should be.
I'm having a hard time troubleshooting because I can't reproduce the problem. My printer handles it fine. Things I have tried:
- Changing the linked image type. I have made transparent .psd, .tif, and .png versions in Photoshop and linked them into InDesign, all with the same result. In all cases choosing the least amount of compression possible.
- Embedding the linked image. Didn't help.
- Changing the Transparency Blend Space back and forth from RGB to CMYK. Didn't help.
- Changing the Transparency Flattener Preset to High Resolution.
- Changing the version of Acrobat compatibility from 5 to 7.
- Changing Adobe PDF Preset from High Quality Print to Smallest File Size.
- Changing Export Layers back and forth from Visible to Visible & Printable.
- Adding PDF/X-1a:2001 standard to the export criteria
I am at my wits' end, I don't know what else to try, since I can't even make it happen. Client reports that she CAN force the document to print correctly by choosing "print as image," which leads me to suspect the issue might lie in how different printers are interpreting the file's transparency. Advice appreciated; I'd like it to work on all printers.
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.