What happens under the hood when you import a PDF into photoshop?

UberTiger

UberTiger

UberTiger

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I do this quite a lot and it 'rasterises' the file during import before I can edit it.

The thing I don't get is the amount of disk space usage and time it takes to rasterise that accompanies this action.

Sometimes a huge PDF (hundreds of megs) will rasterise in 10 seconds and be ready to edit straight away.

Sometimes the PDF may only be a few hundred KB and take a few minutes, or sometimes only a few megs big and take tens of minutes.

Is it to do with the complexity of the PDF or layers? I'm not familiar with the underlying structure of PDFs so this just made me curious, that's all.

Also, what I don't really get is how when I import a PDF that's only a couple of hundred KB, it can use up to a gig of scratch disk space, I can see this because I see my c: remaining space deplete after each consecutive file that I open. What causes this huge usuage, is it normal?

Anyone got any ideas? :)
 
I don't know mate!
Are you saying the ones with more vector images potentially take a much longer time to rasterise than a PDF composed of very few vectors?

Makes sense I guess, I just find it amazing how I can open a 1GB PDF of a promotional poster, busy with images and graphics from one place that will rasterise in 10 seconds, yet I may receive a CAD line drawing with apparently very little details when you look at it and it will take 10 times as long to rasterise.
 
UberTiger said:
I don't know mate!
Are you saying the ones with more vector images potentially take a much longer time to rasterise than a PDF composed of very few vectors?
QUOTE]

At a guess I'd say that's exactly what causes the difference in the time taken.

Any raster images in the the pdf will cause much larger file sizes but are also already in raster format.

Where as a pdf entirely made up of vectors will be tiny in file size terms but then photoshop will have to read the file and render each and every line/shape etc which will take much more time.
Click to expand...
 
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