Working with VERY large files

[Sanpanza]

I am working with a very large file (1.5 Gigs) when opened on an optimized system as far as I can tell. Lots of space on image drive, SSD Scratch drive, iMac Pro with 32 Gb of RAM. File is 36" X 31" @ 240 pixel/inch. Set to 16 bits.

When I use the MIXER BRUSH, the whole system slows down. I am doing painting on about 10 layers but will bring in many, many more layers later.

Should I change the file to 8 bits and, if so, what sort of quality loss can I expect to see if I print to an ink jet printer?

Just trying to speed up my work flow. Every brush stroke sets there machine's think wheel to spin until the calculations are finished.

Thank you kindly for your expertise.

[JJMack]

Mixer brushes can severely tax a machine like my windows workstation.   If I have a large document and zoom way out so the document canvas fits on my display. Select the mixer brush tool set a large tip size and set brush spacing to 1% and do a quick stroke across the canvas. I can watch that stroke being rendered in slow motion.  This stroke was rendering for 2 minuets and was halfway across my display it would take and additional 2 minutes to complete.    I do not do things like that.  My document am not very large and I do use mixer brush with spacing set to 1% and size the tip large.   I use sensible setting so brush lag will not be a pdoblem on my 7 year old slow workstation. A Dell T5600 2GHz Dual Six Core Xeons Processors, Quadro 4000 Display adapter 40GB of ECC Ram and a 256GB SSD. It still gets the job done.

[Sanpanza]

Thank you Jack.

I have a recent machine iMac i7 4 Ghz, Graphics card  Radeon R9 M395X 4096 MB with maxed out RAM (32) , 500 GB SSD scratch disk, only PS open, dedicated content drive, 1 TB SSD drive for system drive. Short of a RAID array, I think I just have to give up the ghost of having everything I want. Sigh.....

I give up on using the mixer brush because I want to paint; not wait. Very frustrating. It would seem that my Large Document File is not suitable for painting with the mixer brush. My last (smaller file) had 156 layers on it and I don't expect this file to have less layers when I am finished.

[rayek.elfin]

My Windows machine is a decade old i7 920 (3.6ghz), and 48gb ram, 1080gtx 8GB. I just tested the mixer brush on a document equal to your settings, and while it's not the fastest thing in the world, it is quite workable. So if my old machine is capable of handling the mixer brush, so should yours. But the mixer is bogged down by multiple additional layers. Hiding these layers seems to help the performance.

Then again, it *is* a Mac, which might have issues with OpenGL performance (not bomblasting the Mac platform here: Apples OpenGL drivers are and have traditionally always been very problematic, and now they are deprecating OpenGL in favour of Metal rather than solving these legacy issues).

I've noticed that when I turn off "Use Graphics Processor" the mixer brush works at least twice as fast. I read similar accounts from other users. OpenGL slows down the mixer brush, it seems. But when we turn off this option we lose all the other functionality in Photoshop. Can't have both in Photoshop. Sigh.

Working in 16bpc mode doesn't really add anything useful. Your inkjet's output colour space won't be able to reach 8bpc, let alone 16bpc. Working in 8bpc speeds up my mixer brush by a factor of at least two.

Having said all this, the mixer brush is *slow*. I wish the devs would have added an instant preview option like Krita, which I prefer to do my painting in anyway.

[Sanpanza]

Thanks rayek.elfin​, I will try give up the notion of 16 bit files and try working without the "OpenGL" to see if that will speed things up.

Appreciate the info. The print would be for fine art presentation with out put on Epson. I understood that I should work in 16 bit then convert to 8 bit when printing to preserve as much color information as possible. Any  thoughts about that ?

[Theresa J]

You shouldn’t have to convert to 8bit for printing, but you may want to convert to 8bit just to make the file size more manageable. You may not notice any loss of information when printed, depending on what’s in the image. The difference between 16bit and 8bit is most noticeable in vignettes or soft transitions between colors and tones.

[Sanpanza]

Hi Theresa, thanks for your input. When I am working with the paintbrush on files that are over 4 gigs, brushes like Kyles Water Colors and mixer brush slow way down. @rayek.elfin seems to think that turning off "Use Graphics Processor" and hiding layers may speed up the process. I will try this next

The reason I work in 16 bits is to hold onto complex color gradations when I convert to 8 bit. My understanding is that I will maintain color fidelity when I have a large color palette to deal with. Any thoughts on this matter?

Additionally, sometimes I have to bring in 8 bit images into a 16 big file, so some layers are at 8 bits and some layers are at 16 bits. Am I causing problems for myself if I do this?

[Theresa J]

A document can’t be both 8bit and 16bit. When you bring an 8bit image into a 16bit document it converts to 16bit, and it won’t gain any quality by converting up to 16bit.

I’ve created some very large composite images in 8bit because of file size and speed. My prints still look great, but my work isn’t filled with complex color gradations. You should run some print tests to determine just how much you gain or lose.

[SheyDak]

By any chance do you have a file that large like the 1.5gb you mention with all images/layers marked with FOR PC TEST ONLY so I can use it to see if a system I build can handle real working files? I want to see if the computer can handle it without crashing. I'll keep it for my use only, no share or sell or anything, test only. That would be so cool : ) 

[davescm]

Just make yourself a test file. The OP gave the file size and ppi in the first post. Duplicate and transform some layers, add layer blending modes then try and carry out some common operations

Dave

[D Fosse]

The OP gave the size as 36 x 31 inches at 240 ppi. In Photoshop terms, that means the file is 8640 x 7440 pixels.

That's on the biggish side, but by no means extreme. If I put two camera files side by side, that more than covers it. To get a really big file out of that, you need to add a lot of layers.

Nothing is going to crash. Photoshop doesn't crash on big files, it just works slower. But it'll get there.

The one single component in the entire system which is critical here, is the scratch disk. That's disk space Photoshop needs to store all that temporary working data as it goes along. With really big files, the PS scratch file can be a half terabyte or more. You need to have all that disk space available, on a disk that is as fast as possible.

People will probably tell you that you need a lot of RAM - but with in excess of 500 GB to handle, 32 or 64 GB RAM doesn't really enter into the equation.