Photoshop CS Scratch Disk Problem with big files (.psb)

614 views9 repliesLast post: 1/17/2004
Im working on a bigformat scanning project where i have to assamble Pictures of 35000 x 28000 pixels with ~18 layers. I was desperatly waiting for PS CS because now those file sizes are supported. I have always 2 files of 18000 x 28000 to assamble which i scanned in Photoshop 7 - but as soon as i try to put anything into my new created and blank 35000x 28000 file i get a "scatch disk is full error". But there are still 16 gb free and only 3.5gb used for scratch ( I work with a 1,4 GHZ Athlon and 512 MB RAM, Win2000). I followed all the ideas given in the FAQ on that problem - but nothing worked. Even if i reduce the layers to one background layer - same error.

Is there anyone working with files that large? How large will the scratch need be for a file like this (any formula to calculate this)?

What sense does it make to introduce the *.psb format if you are unable to produce files in this size because of scratch problems?

thx for help ...
#1
How are you determining the free scratch space? In point of fact, a black file of that size may not create a huge scratch but copying or trying to drag & drop something in that image may indeed imeediately require a huge jump in the scratch space. Photoshop would examine the function you are trying to do and check the amount of scratch space required and find that doing the function will create too big of a scratch for the function, hense the warning.

I've dedicated a 50gig partition of an array with a secondary scratch of whatever free space is on a 250 gig drive and I've been able to work on large PSB's in 16 bit without ever getting a warning.

Chris Cox was able to produce a 500gig image but it took all afternoon to save and 2 terrabytes of scratch space. So, it's doable.
#2
The scratch file of 3,5 GB was produced by loading the 18000 x 28000 pixel image (half of the needed size and limit in photoshop 7 - nearly). But anyway - is there a way of determining the needed scratch space for a certain image size (and layer number)? Because now I have to find out if I need to buy a 60, 120 or even 250 GB HD for scratchdisk in order to complete this project.

thx for your help.
andreas.
#3
The easy math is width*height*channels*depth*layers (* history states)

There is no easy way to account for compression, and history states will only store the objects that changed.

35000 x 28000 in 8 bit RGB is 2.74 Gig.
Yes, I can see how that would fill a measly little 16 Gig scratch drive rather quickly.

Wild - 200 and 250 Gig disks are cheap if you shop around....

(and it was only a 250 Gig image with 1 terabyte of scratch disk - but it did take all afternoon)
#4
Chris. . .

Sorry to misquote you bud. . .but whats a couple terabytes beween friends <BG>.

Andreas, if in doubt get the biggest you can. . .the old school of thought regarding ram & scratch disk use is pretty much out the window now that we have PSB and 16 bit layered images. Get all the ram and scratch space you can if you're gonna be working in PSB.
#5
Thanks so far - Ill give a report on the subject and the solution as soon as the disk (200 GB) arrived and I built it in ...
#6
Ah, yes, time for that old joke -

"How much disk and scratch do I need for Photoshop?"

"More."

-Scott
#7
Well to post the result of the operation:
After some trouble with cache/win2000 i got the raid installed and now photoshop cs got its 320 Gb scratch disk. with this one its no problem to create the file size i wanted - and scratch file size is at about 50 gig for my scanfile.

so it seems that to the new photoshop some new hardware is needed - hope adobe get a little support by HD industry :)
#8
500gb drives are something like £500

100 MB cost me that about 10 years ago...
#9
When Photoshop says the disk is full, it's because the OS reported that the disk is full, or would be full if Photoshop allocted the scratch space it requested.
#10