16bit vs 8bit CS4

SuperAkuma · 08-29-2009, 10:49 PM

Is there a difference between to two besides the size of the image? I noticed that at default it is at 16bit when I process a RAW image from my K20D. The image are HUGE and it takes forever for my computer to process a filter. I have a fairly power computer, 64bit os, 8GB of ram and a quad core processor.

Most of my work I only view online and I do some printing. Is there any reason why the files should be at 16 bit instead of 8 bit?

flippedgazelle · 08-29-2009, 11:00 PM

Yep, 16 bit means there's 16 bits of info per color channel per pixel, whereas with 8 bit there's... 8. One important aspect of this is that tones can be rendered more subtly, and also gradients are smoother (no banding).

How long is "forever"? And what filters? I have a quad core CPU, 8GB, Vista x64, and things move along speedily, IMO. Sharpening and whatnot takes just a second or 2. Is your scratch disk set for a drive other than the drive on which CS4 is installed?

SuperAkuma · 08-29-2009, 11:03 PM

Originally posted by flippedgazelle

Yep, 16 bit means there's 16 bits of info per color channel per pixel, whereas with 8 bit there's... 8. One important aspect of this is that tones can be rendered more subtly, and also gradients are smoother (no banding).

How long is "forever"? And what filters? I have a quad core CPU, 8GB, Vista x64, and things move along speedily, IMO. Sharpening and whatnot takes just a second or 2. Is your scratch disk set for a drive other than the drive on which CS4 is installed?

Forever is close to 5 minutes. I have lots of layers. The file size is close to 300mb in 16 bit. In 8 bit it is under 100mb.

Sharping is no problem, it is when I use surface blur. The surface blur was set pretty high. I just tested it again, at 16 bit it was about 5 minute to rendure the surface blur filter. At 8 bit, it was instant on the same image.

flippedgazelle · 08-30-2009, 09:16 AM

Originally posted by SuperAkuma

Forever is close to 5 minutes. I have lots of layers. The file size is close to 300mb in 16 bit. In 8 bit it is under 100mb.

Sharping is no problem, it is when I use surface blur. The surface blur was set pretty high. I just tested it again, at 16 bit it was about 5 minute to rendure the surface blur filter. At 8 bit, it was instant on the same image.

Hmm, I see what you mean. I just took an image (16 bits per channel), made 5 layers, then ran surafce blur with settings of 51, 134, and CS4 took over 4 minutes to process. Convert the image to 8 bits per channel, and the operation took around 10 seconds. Vista's task manager shows all 4 CPU cores working at nearly 100%.

Maybe test a couple of images at 16 bit and 8 bit, and if you don't discern a difference between the 2, go for 8 bit. Maybe do all operations other than surace blur in 16 bit mode, then switch to 8 bit for surface blur.

ivoire · 08-30-2009, 09:40 AM

I tried this on a dual core 4gb laptop and the slowdown is huge at 16 bits. Switching to 8bit with that much surface blur (took a few seconds) probably won't make much of a difference for the layer. I will have to experiment with the 16bit aspect in relation to noise correction and see if this might improve high iso images also.

Jim Royal · 08-30-2009, 01:30 PM

Originally posted by SuperAkuma

Forever is close to 5 minutes. I have lots of layers. The file size is close to 300mb in 16 bit. In 8 bit it is under 100mb.

I can confirm that Surface blur is significantly slower with applied to 16-bit images. I tested with a 4000x4000 pixel image fulled with random noise. At 8-bit, the blur took about two seconds. At 16-bit, it took about 30 seconds.

Still, that's nowhere near five minutes. I have a quad-core Xeon machine with 4 GB RAM running Mac OS X 10.5.8.

flippedgazelle · 08-30-2009, 05:56 PM

Originally posted by Jim Royal

I can confirm that Surface blur is significantly slower with applied to 16-bit images. I tested with a 4000x4000 pixel image fulled with random noise. At 8-bit, the blur took about two seconds. At 16-bit, it took about 30 seconds.

Still, that's nowhere near five minutes. I have a quad-core Xeon machine with 4 GB RAM running Mac OS X 10.5.8.

It all depends on how big the file is, and what the surface blur settings are.

My PC can do a 4000x4000 16 bit image almost instantaneously, with surface blur settings of 1, 2. Add about 5 layers, crank the blur settings up to the max, and then you're talking about minutes.

Jim Royal · 08-30-2009, 06:50 PM

Originally posted by flippedgazelle

Add about 5 layers, crank the blur settings up to the max, and then you're talking about minutes.

Then the key element is whether Photoshop is keeping the entire operation in RAM or not. If you're experiencing severe slowdowns in PS, it would be worthwhile checking the Activity Monitor / Task Manager and keep an eye on the disk activity. If PS is using the hard disk during a Surface Blur, then it doesn't matter how fast the processor is. Performance will be bound entirely by the speed of the hard disk.

ivoire · 08-30-2009, 07:16 PM

A solid state drive would decrease the processing time. But before I made that leap I'd determine if 8bit surface blur (at his processing levels) would be acceptable. Based on the times I suspect 8bit is held in ram and 16 is a disk swap. Anyone with a SSD want to test this and post the result?

flippedgazelle · 08-30-2009, 10:46 PM

Originally posted by Jim Royal

Then the key element is whether Photoshop is keeping the entire operation in RAM or not. If you're experiencing severe slowdowns in PS, it would be worthwhile checking the Activity Monitor / Task Manager and keep an eye on the disk activity. If PS is using the hard disk during a Surface Blur, then it doesn't matter how fast the processor is. Performance will be bound entirely by the speed of the hard disk.

It's mostly CPU-bound. I have a 3gb RAM disk setup, and while the surface blur operation is in progress, there is almost no HDD access, but only about 300mb of the RAM disk is used.

Jim Royal · 08-31-2009, 04:29 AM

Originally posted by flippedgazelle

It's mostly CPU-bound. I have a 3gb RAM disk setup, and while the surface blur operation is in progress, there is almost no HDD access, but only about 300mb of the RAM disk is used.

Yeah, I just checked again, duplicating the conditions. Five minutes on Mac OS X, too. So, it is not hardware or OS-dependent.

The weird thing is why having more layers makes such a difference. It should be applying the filter to a single layer.

ivoire · 08-31-2009, 06:20 AM

You might check your Vista performance setting and change it to "adjust for best performance" as opposed to the default of "let windows choose". That should give you a surface blur performance improvement. If you are not familiar with this, select:

control panel
system
remote settings
advanced
performance
and click 'adjust for best performance'
apply
ok
then reboot to have it take effect

flippedgazelle · 08-31-2009, 01:58 PM

Originally posted by Jim Royal

Yeah, I just checked again, duplicating the conditions. Five minutes on Mac OS X, too. So, it is not hardware or OS-dependent.

The weird thing is why having more layers makes such a difference. It should be applying the filter to a single layer.

You got me thinking... I took a 3872 x 2592 file (standard K2000 10mp file) and doubled the size in each direction, thus creating a file that is 4x the size of the original. I ran surface blur, and sure enough it took about 4 minutes to complete. So it's not just layers, it's the actual size of the file.

Weird.

When I apply surafce blur, even though I'm ostensibly working on only one layer, it is appllied to all layers.

bobrapp · 08-31-2009, 02:06 PM

Originally posted by SuperAkuma

Is there a difference between to two besides the size of the image? I noticed that at default it is at 16bit when I process a RAW image from my K20D. The image are HUGE and it takes forever for my computer to process a filter. I have a fairly power computer, 64bit os, 8GB of ram and a quad core processor.

Most of my work I only view online and I do some printing. Is there any reason why the files should be at 16 bit instead of 8 bit?

What OS are you running? I had a similar problem with vista-64 until I changed the performance settings.

Cloggie_UK · 08-31-2009, 02:24 PM

Originally posted by ivoire

You might check your Vista performance setting and change it to "adjust for best performance" as opposed to the default of "let windows choose". That should give you a surface blur performance improvement. If you are not familiar with this, select:

control panel
system
remote settings
advanced
performance
and click 'adjust for best performance'
apply
ok
then reboot to have it take effect

This could help on some systems. Vista is very memory hungry and all the visual GUI effects do have quite some overhead. If your system is somewhat older and you haven't got the latest hardware and only 2-4Gb RAM, turning all the visual effects off will have some impact.

Roll on Windows 7

If you however have an up to date system hardware wise and plenty of RAM and one of the latest graphics cards with a multi core GPU, you will hardly notice the difference.

My system is up to date hardware wise but I still turn it off as I a) find it annoying and b) pointless. I don't need smooth scrolling combo boxes, animated menus etc. I like my OS to be snappy. It probably still is with all the eye candy turned on but it is perceived sluggish due to all the visual trickery.

08-29-2009, 10:49 PM	#1
SuperAkuma Veteran Member Join Date: Jul 2007 Location: Bay Area, CA Photos: Gallery Posts: 445	16bit vs 8bit CS4 Is there a difference between to two besides the size of the image? I noticed that at default it is at 16bit when I process a RAW image from my K20D. The image are HUGE and it takes forever for my computer to process a filter. I have a fairly power computer, 64bit os, 8GB of ram and a quad core processor. Most of my work I only view online and I do some printing. Is there any reason why the files should be at 16 bit instead of 8 bit?

08-29-2009, 11:03 PM	#3
SuperAkuma Veteran Member Join Date: Jul 2007 Location: Bay Area, CA Photos: Gallery Posts: 445 Original Poster	Originally posted by flippedgazelle Yep, 16 bit means there's 16 bits of info per color channel per pixel, whereas with 8 bit there's... 8. One important aspect of this is that tones can be rendered more subtly, and also gradients are smoother (no banding). How long is "forever"? And what filters? I have a quad core CPU, 8GB, Vista x64, and things move along speedily, IMO. Sharpening and whatnot takes just a second or 2. Is your scratch disk set for a drive other than the drive on which CS4 is installed? Forever is close to 5 minutes. I have lots of layers. The file size is close to 300mb in 16 bit. In 8 bit it is under 100mb. Sharping is no problem, it is when I use surface blur. The surface blur was set pretty high. I just tested it again, at 16 bit it was about 5 minute to rendure the surface blur filter. At 8 bit, it was instant on the same image. Last edited by SuperAkuma; 08-29-2009 at 11:09 PM.

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08-29-2009, 11:00 PM	#2
flippedgazelle Veteran Member Join Date: Apr 2009 Location: NJ, USA Photos: Albums Posts: 1,270	Yep, 16 bit means there's 16 bits of info per color channel per pixel, whereas with 8 bit there's... 8. One important aspect of this is that tones can be rendered more subtly, and also gradients are smoother (no banding). How long is "forever"? And what filters? I have a quad core CPU, 8GB, Vista x64, and things move along speedily, IMO. Sharpening and whatnot takes just a second or 2. Is your scratch disk set for a drive other than the drive on which CS4 is installed?

08-30-2009, 09:16 AM	#4
flippedgazelle Veteran Member Join Date: Apr 2009 Location: NJ, USA Photos: Albums Posts: 1,270	Originally posted by SuperAkuma Forever is close to 5 minutes. I have lots of layers. The file size is close to 300mb in 16 bit. In 8 bit it is under 100mb. Sharping is no problem, it is when I use surface blur. The surface blur was set pretty high. I just tested it again, at 16 bit it was about 5 minute to rendure the surface blur filter. At 8 bit, it was instant on the same image. Hmm, I see what you mean. I just took an image (16 bits per channel), made 5 layers, then ran surafce blur with settings of 51, 134, and CS4 took over 4 minutes to process. Convert the image to 8 bits per channel, and the operation took around 10 seconds. Vista's task manager shows all 4 CPU cores working at nearly 100%. Maybe test a couple of images at 16 bit and 8 bit, and if you don't discern a difference between the 2, go for 8 bit. Maybe do all operations other than surace blur in 16 bit mode, then switch to 8 bit for surface blur.

08-30-2009, 09:40 AM	#5
ivoire Veteran Member Join Date: Mar 2007 Photos: Gallery Posts: 3,381	I tried this on a dual core 4gb laptop and the slowdown is huge at 16 bits. Switching to 8bit with that much surface blur (took a few seconds) probably won't make much of a difference for the layer. I will have to experiment with the 16bit aspect in relation to noise correction and see if this might improve high iso images also.

08-30-2009, 01:30 PM	#6
Jim Royal Senior Member Join Date: Oct 2006 Location: Montreal Photos: Gallery Posts: 179	Originally posted by SuperAkuma Forever is close to 5 minutes. I have lots of layers. The file size is close to 300mb in 16 bit. In 8 bit it is under 100mb. I can confirm that Surface blur is significantly slower with applied to 16-bit images. I tested with a 4000x4000 pixel image fulled with random noise. At 8-bit, the blur took about two seconds. At 16-bit, it took about 30 seconds. Still, that's nowhere near five minutes. I have a quad-core Xeon machine with 4 GB RAM running Mac OS X 10.5.8.

08-30-2009, 05:56 PM	#7
flippedgazelle Veteran Member Join Date: Apr 2009 Location: NJ, USA Photos: Albums Posts: 1,270	Originally posted by Jim Royal I can confirm that Surface blur is significantly slower with applied to 16-bit images. I tested with a 4000x4000 pixel image fulled with random noise. At 8-bit, the blur took about two seconds. At 16-bit, it took about 30 seconds. Still, that's nowhere near five minutes. I have a quad-core Xeon machine with 4 GB RAM running Mac OS X 10.5.8. It all depends on how big the file is, and what the surface blur settings are. My PC can do a 4000x4000 16 bit image almost instantaneously, with surface blur settings of 1, 2. Add about 5 layers, crank the blur settings up to the max, and then you're talking about minutes.

08-30-2009, 06:50 PM	#8
Jim Royal Senior Member Join Date: Oct 2006 Location: Montreal Photos: Gallery Posts: 179	Originally posted by flippedgazelle Add about 5 layers, crank the blur settings up to the max, and then you're talking about minutes. Then the key element is whether Photoshop is keeping the entire operation in RAM or not. If you're experiencing severe slowdowns in PS, it would be worthwhile checking the Activity Monitor / Task Manager and keep an eye on the disk activity. If PS is using the hard disk during a Surface Blur, then it doesn't matter how fast the processor is. Performance will be bound entirely by the speed of the hard disk.

08-30-2009, 07:16 PM	#9
ivoire Veteran Member Join Date: Mar 2007 Photos: Gallery Posts: 3,381	A solid state drive would decrease the processing time. But before I made that leap I'd determine if 8bit surface blur (at his processing levels) would be acceptable. Based on the times I suspect 8bit is held in ram and 16 is a disk swap. Anyone with a SSD want to test this and post the result?

08-30-2009, 10:46 PM	#10
flippedgazelle Veteran Member Join Date: Apr 2009 Location: NJ, USA Photos: Albums Posts: 1,270	Originally posted by Jim Royal Then the key element is whether Photoshop is keeping the entire operation in RAM or not. If you're experiencing severe slowdowns in PS, it would be worthwhile checking the Activity Monitor / Task Manager and keep an eye on the disk activity. If PS is using the hard disk during a Surface Blur, then it doesn't matter how fast the processor is. Performance will be bound entirely by the speed of the hard disk. It's mostly CPU-bound. I have a 3gb RAM disk setup, and while the surface blur operation is in progress, there is almost no HDD access, but only about 300mb of the RAM disk is used.

08-31-2009, 04:29 AM	#11
Jim Royal Senior Member Join Date: Oct 2006 Location: Montreal Photos: Gallery Posts: 179	Originally posted by flippedgazelle It's mostly CPU-bound. I have a 3gb RAM disk setup, and while the surface blur operation is in progress, there is almost no HDD access, but only about 300mb of the RAM disk is used. Yeah, I just checked again, duplicating the conditions. Five minutes on Mac OS X, too. So, it is not hardware or OS-dependent. The weird thing is why having more layers makes such a difference. It should be applying the filter to a single layer.

08-31-2009, 06:20 AM	#12
ivoire Veteran Member Join Date: Mar 2007 Photos: Gallery Posts: 3,381	You might check your Vista performance setting and change it to "adjust for best performance" as opposed to the default of "let windows choose". That should give you a surface blur performance improvement. If you are not familiar with this, select: control panel system remote settings advanced performance and click 'adjust for best performance' apply ok then reboot to have it take effect

08-31-2009, 01:58 PM	#13
flippedgazelle Veteran Member Join Date: Apr 2009 Location: NJ, USA Photos: Albums Posts: 1,270	Originally posted by Jim Royal Yeah, I just checked again, duplicating the conditions. Five minutes on Mac OS X, too. So, it is not hardware or OS-dependent. The weird thing is why having more layers makes such a difference. It should be applying the filter to a single layer. You got me thinking... I took a 3872 x 2592 file (standard K2000 10mp file) and doubled the size in each direction, thus creating a file that is 4x the size of the original. I ran surface blur, and sure enough it took about 4 minutes to complete. So it's not just layers, it's the actual size of the file. Weird. When I apply surafce blur, even though I'm ostensibly working on only one layer, it is appllied to all layers.

08-31-2009, 02:06 PM	#14
bobrapp Senior Member Join Date: Sep 2006 Location: Grand Junction Colorado Posts: 209	Originally posted by SuperAkuma Is there a difference between to two besides the size of the image? I noticed that at default it is at 16bit when I process a RAW image from my K20D. The image are HUGE and it takes forever for my computer to process a filter. I have a fairly power computer, 64bit os, 8GB of ram and a quad core processor. Most of my work I only view online and I do some printing. Is there any reason why the files should be at 16 bit instead of 8 bit? What OS are you running? I had a similar problem with vista-64 until I changed the performance settings.

08-31-2009, 02:24 PM	#15
Cloggie_UK Forum Member Join Date: Nov 2006 Location: West Sussex, United Kingdom Photos: Gallery Posts: 87	Originally posted by ivoire You might check your Vista performance setting and change it to "adjust for best performance" as opposed to the default of "let windows choose". That should give you a surface blur performance improvement. If you are not familiar with this, select: control panel system remote settings advanced performance and click 'adjust for best performance' apply ok then reboot to have it take effect This could help on some systems. Vista is very memory hungry and all the visual GUI effects do have quite some overhead. If your system is somewhat older and you haven't got the latest hardware and only 2-4Gb RAM, turning all the visual effects off will have some impact. Roll on Windows 7 If you however have an up to date system hardware wise and plenty of RAM and one of the latest graphics cards with a multi core GPU, you will hardly notice the difference. My system is up to date hardware wise but I still turn it off as I a) find it annoying and b) pointless. I don't need smooth scrolling combo boxes, animated menus etc. I like my OS to be snappy. It probably still is with all the eye candy turned on but it is perceived sluggish due to all the visual trickery.