Displaying PDF documents on iPad - Color Problems

Question

I've built a PDF reader for the iPad and I've noticed some color problems when doing a side-by-side comparison of the document in preview verus the simulator and device.

The best way to describe it is to say that the colors have become more intense. Any discrepancies between similar colors used in close proximity have become more noticeable while all the colors seem brighter in general.

Answer 1

Despite the hype connecting the iPad to the print industry, it doesn't supply a device calibrated CMYK profile installed. As a result, any PDFs with CMYK content tend to look quite crazy. Conversely, I believe that it handles conversions from Adobe RGB to the iPad's screen very well indeed, so you'd be highly recommended to find a way to adjust how you're outputting your PDFs or to find a tool that can do a conversion after the fact.

I've dealt with this only from the implementation side so don't have direct experience, but I believe that at least in InDesign it's a simple export toggle.

Answer 2

When I wrote that I forgot to consider that the bitmap images I was using were EXPORTED for the web from Photoshop (i.e. save for web), and therefore by default, they displayed correctly. Looking at my print PDFs that have images embedded in them, I can see that any of them that use the wrong profile have high contrast and bad coloring in the images and the vector elements.

I suggest that for images you want to display on the iPad, that you try either exporting them for web, making sure that you have enough resolution to look good on the iPad, or else saving them with an RGB profile, either Adobe RGB or working sRGB - see which looks best.

Note that there is a difference between "assigning" a color profile and "converting" to a color profile, as one of them is "destructive" and degrades the image quality a bit when making the conversion, and the other is not. You might try both with your images - save a series with a combination of these 2 variables - which profile and which method to get there - and see what works best with your images.

I might do the experiment myself soon with different types of images and see what looks best on the iPad.

Keep in mind that sRGB profile was created for computer monitors and Adobe RGB 1998 is a good RGB profile for digital printing (and more), but the iPad is neither really - maybe soon there will be a profile created for it :). Since I haven't tested it in-depth I'd suggest you try both and see what turns out true-to-color for you.

There are a couple of good blogs I have seen about using Photoshop for iPhone & iPad design. This one seems to be in-depth. I plan on reading it soon:

http://bjango.com/articles/photoshop/