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After Effects as a tool for iDevice animations
creating my 2nd iPad app, a childrens book app. Target resolution is for the iPad 2, so 132 pixels/inch.
Steps to reproduce this issue:
1. in Adobe Photoshop CS5.5, create any PSD file with a few layers, at 132 ppi, save it.
2. generate a PNG file from the PSD, use Save As (not Save for Web), verify the 132ppi setting holds into the file, it will.
3. Add same PNG file to your Xcode/ iPad simulator and all is well, the image appears on your computer monitor LCD screen as it does in the simulator (eg, no scaling).
d. import the PSD into AE (v10.5) CS5.5 as a composition. Animate anything and save out some PNG’s (lets say 30 of them).
e. import any one of the AE-exported PNG files into Photoshop – view its resolution now in the Image menu – it will read 72ppi !
This image will not appear correctly on any iPad simulator !
Can AE not render PNG files without transcoding them to a lower intrinsic resolution ? If so, how to avoid this ?
Warm regards,
Chris
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6 Replies
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DPI/PPI means nothing with fixed resolution output devices like screens. You simply need the total resolution of the screen which for the iPad2, if I’m not mistaken, is 1024×768.
What may be changing are the actual pixel dimensions. I would investigate your workflow from that angle.
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as Ive said, the steps to reproduce the problem mean that 132ppi goes in, and 72ppi comes out.
The actual document dimensions dont bear on this matter….
Warm regards,
Chris
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Could you output the files in After Effects at the correct pixel dimensions as a PNG sequence then use Photoshop to batch convert the sequence to the appropriate resolution?
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yes is the short answer however – that would imply up-rezzing in PS of the AE-exported files, which will lower overall quality.
Photoshop has this same function “Save for Web….” (ie, outputting to the old standard of 72ppi) but if one simply uses the “Save As” dialogue the pixels per inch attribute will not be affected.
Just for the record, last nite I tried the same PNG export problem on AECC, to no avail, it too unfortunately also de-rez’s the PNG file quality.
When I find a workaround, I will update here…. perhaps Nuke or Motion do not suffer this issue….
Warm regards,
Chris
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Not sure I agree, here’s the math.
iPad resolution = 1024×768 @ 132ppi.
Make the graphic and After Effects Comp 1840 x 1382 @ 72ppi (Roughly 1.8 times the size)
Output PNG sequence.
Batch change the resolution in Photoshop.
Try a test with a single frame to see whether it works.
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appreciate your post Ridley, although I didnt understand the 1.8 figure.
Still the sugg to batch change the resolutions in Photoshop to 132ppi was helpful, and allowed me to complete my animation just fine ! So THANK YOU ! But relevant is the fact that the batch changes must be accompanied *without resampling* (this was just left unchecked if anyone is following this thread).
Still Ive become aware that Maya 2013 does not have the PPI output limitation that AE does, it will handle whatever number you feed it. Autodesk calls this attribute “resolution units”.
Warm regards,
Chris
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