Acrobat displays images at the system default of 96 ppi.
In Acrobat go to Preferences and under Page Display, you can insert a Custom Resolution which will likely fix your issue.
Be aware that this is an individual setting, other computers may not have this set.
This might sound very silly, sorry. But when you open the created PDF, make sure you're looking at the PDF at 100% zoom level. I've had a lot of clients telling me the same issue when they're looking at the PDF zoomed in (which gives you a blurry image since it's all lowres)
InDesign shouldn't touch your images of you don't downsample them. Just make sure that you use Maximum quality for your image options when exporting.
Why use Maximum Quality? Just use no compression.
And screenshots are better done as png rather than jpeg.
Well he didn't say it were screenshots. Just "web images".
If it are screenshot I'd personally go with the zip format, which gives better results.
Ah very true - I've been taking too many screenshots lately.
Note: The only way I have found around this is to re-create the images as 150ppi however need another solution as they need to be 72ppi.
Why do they need to be 72? If increasing the resolution solves the problem just use a larger pixel dimension. So if your 150ppi image's dimensions are 5x5 you could resize its dimensions to 10.417 x 10.417 and get 72ppi—then scale it to 5x5 in the layout or 48.1%. It's the effective resolution—the resolution after scaling—that gets exported
Thanks for the replies a couple answers below:
- They are images that have been designed in Photoshop and 'saved for web' at maximum. (Also tried saving PNG, TIFF and even placing the PSD into InDesign)
- To have them any larger than 72ppi they would need to be re-done from scratch so this isn't really a solution
- Yes PDF is being zoomed at 100%
It looks like changing the resolution in Acrobat from 96ppi to 72ppi is the only solution that seems to work, I guess we will have to tell all our clients to change their resolution in Acrobat, not ideal.
Thanks everyone for your help
Acrobat looks to the system to get the monitor resolution so that 100% view simulates the actual print size at 100%. InDesign does the same. It might be 96ppi on your system but on my 27" iMac it's 108, so it's entirely dependent on the user's hardware:
There's no way you can control a user's viewing habits—how do you know what percentage they will view at? Maybe it's 125%? You could ask them to change their Acrobat view preference, but it would be the same as asking them to choose a different zoom percentage. If you want images to look good at different zooms you have to increase the pixel dimensions.
Maybe I was bit vague with my point.
The solution isn't really to ask everyone to change their setup. What I was getting at is that everyone's computer is different so you get different results when using 72 ppi. As Acrobat uses the display (your monitor) as the resolution for displaying images. Whereas web browsers are set at 72.
It would be best to use higher res images for the pdfs, and create lower res images for the web.
This would be the norm.