Up-Rez in Raw for Printing?

[Paul Sumi]

I use Capture One, which gives one the option to process a Raw file at native resolution, lower, and, I presume, higher as well.

Has anyone tried up-rezing in Raw for printing instead of in Photoshop or other means?

Thanks,

Paul

[Ernst Dinkla]

I use Capture One, which gives one the option to process a Raw file at native resolution, lower, and, I presume, higher as well.

Has anyone tried up-rezing in Raw for printing instead of in Photoshop or other means?

Thanks,

Paul

What would be the advantage to uprez in Raw ?   I can see some advantage in Raw downsampling with the right algorithms as it could shift noise to higher frequencies but not the other way around.  Better stick to the resolution as captured and no resampling at all but on the fly at printing time while leaving the archived file untouched. Like the Qimage workflow allows.


met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/

[JeffKohn]

The only thing up-rezzing in raw will gain you is larger file sizes for your working/master files, which in turn means slower performance in Photoshop.

[Paul Sumi]

The only thing up-rezzing in raw will gain you is larger file sizes for your working/master files, which in turn means slower performance in Photoshop.

So you're saying it's better to print (giving a hypothetical situation) a very large print at 100 DPI native resolution rather than uprez to 300 DPI?

Paul

[JeffKohn]

So you're saying it's better to print (giving a hypothetical situation) a very large print at 100 DPI native resolution rather than uprez to 300 DPI?

Paul

I didn't say that. I'm just saying if you're going to up-rez I see no benefit to doing so at the RAW conversion stage.

If I were going to print at 100ppi native resolution (not something I'd be likely to do),  I would up-rez at the end, just before output sharpening.

[Ernst Dinkla]

So you're saying it's better to print (giving a hypothetical situation) a very large print at 100 DPI native resolution rather than uprez to 300 DPI?

Paul

It will be upsampled anyway with a print task like that. But for the next job you may need good downsampling. So you check what the best software for resampling is at printing time or for web use etc. Though the printer drivers are improved on that aspect it may be wiser to let the application you print from do the job and you make sure you get the application with the best resampling routines. With the same logic you prefer to keep the Raw file or the file processed from Raw as original as it can be. Up and downsampling of the original for every kind of output and saving it will degrade that file fast. As long as there is no evidence that Raw upsampled gives better image quality than upsampling a Tiff (for example) at printing time there is no reason to prefer the first method.


met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/

[Paul Sumi]

I didn't say that. I'm just saying if you're going to up-rez I see no benefit to doing so at the RAW conversion stage.

If I were going to print at 100ppi native resolution (not something I'd be likely to do),  I would up-rez at the end, just before output sharpening.

I guess I'm now trying to understand why up-rezing right before printing yields a better print than up-rezing at the raw processing stage.  Assume I don't care that the file is larger than native resolution and takes longer to manipulate in Photoshop.

Paul

[JeffKohn]

I guess I'm now trying to understand why up-rezing right before printing yields a better print than up-rezing at the raw processing stage.  Assume I don't care that the file is larger than native resolution and takes longer to manipulate in Photoshop.

Paul

It's not that one is better than the other. I'd say there's no real difference. So then the question becomes, why up-rez in the raw converter when it means larger file and worse performance in Photoshop while editing? What do you gain?

And as Ernst pointed out, if you upsize at the beginning of your workflow, you're kind of locked-in your output size. Keeping your master file at the native resolution gives you more flexibility if you ever need to support multiple output sizes.

[Paul Sumi]

It will be upsampled anyway with a print task like that. But for the next job you may need good downsampling. So you check what the best software for resampling is at printing time or for web use etc. Though the printer drivers are improved on that aspect it may be wiser to let the application you print from do the job and you make sure you get the application with the best resampling routines. With the same logic you prefer to keep the Raw file or the file processed from Raw as original as it can be. Up and downsampling of the original for every kind of output and saving it will degrade that file fast. As long as there is no evidence that Raw upsampled gives better image quality than upsampling a Tiff (for example) at printing time there is no reason to prefer the first method.


met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/

Hi Ernst,

I think I need to clarify.  When I said up-rez the raw, I meant outputting a TIFF file at greater than native resolution. I normally process my raws to a tiff file at native resolution, 16bit, pro photo color.  There are times when I may output a smaller tiff specifically for Internet usage.

What brought this question up is I've got some older 4 or 6 megapixel raw files.  This got me wondering if outputting a larger than native resolution tiff might have an advantage over up-rezing later.

If anyone has actually done a comparison, I'd be very interested in the results.

Thanks,

Paul

[Paul Sumi]

It's not that one is better than the other. I'd say there's no real difference. So then the question becomes, why up-rez in the raw converter when it means larger file and worse performance in Photoshop while editing? What do you gain?

And as Ernst pointed out, if you upsize at the beginning of your workflow, you're kind of locked-in your output size. Keeping your master file at the native resolution gives you more flexibility if you ever need to support multiple output sizes.

Thanks for your replies and patience, Jeff.  As you'll see above in my reply above to Ernst, this whole question came up because I have some smaller (4 & 6 megapixel) raws from which tiffs would have to be up-rezzed anyway to make decent large prints.

Best,

Paul

[Ernst Dinkla]

Hi Ernst,

I think I need to clarify.  When I said up-rez the raw, I meant outputting a TIFF file at greater than native resolution. I normally process my raws to a tiff file at native resolution, 16bit, pro photo color.  There are times when I may output a smaller tiff specifically for Internet usage.

What brought this question up is I've got some older 4 or 6 megapixel raw files.  This got me wondering if outputting a larger than native resolution tiff might have an advantage over up-rezing later.

If anyone has actually done a comparison, I'd be very interested in the results.

Thanks,

Paul

My intuition says that it may be even worse but I have no proof. If the upsampling is done before further noise reduction (if even possible) there could be a shift of the noise to lower, more visible frequencies. I also wonder whether upsampling artefacts show more from a Raw file without noise reduction than from one where noise reduction has already been done. When both Raw and Tiff have had the noise reduction the only factor that can influence the result is the quality of the upsampling routine. In my opinion the last is the most important factor especially with upsampling ratios above 2x. I have already sketched the practical advantages of upsampling at the end of the workflow.

My interest in this issue is actually based on the opposite. There has been a discussion on DPreview whether one can compare different sensors with different resolutions by downsampling the images to a common resolution/size and use the signal/noise numbers to rank the sensors. DxO does that more or less. Lanczos does a good job at noise reduction when downsampling but not all resampling routines behave the same (there's more to it though). I asked Mike Chaney if it was a good idea to shift the downsampling (when needed) in Qimage to the Raw input there (and reduce noise at the same time) instead of later on in the process. He answered that the (adjustable) anti-aliasing filter also used in the Qimage downsampling has far more impact on noise reduction than the choice of the algorithm or where the downsampling should be done. A down to earth reply that couldn't be more clear.


met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/

[DeanChriss]

I use Capture One, which gives one the option to process a Raw file at native resolution, lower, and, I presume, higher as well.

Has anyone tried up-rezing in Raw for printing instead of in Photoshop or other means?

Thanks,

Paul

I've tried this, and you'll typically do slightly better increasing the resolution in Photoshop using the bicubic smoother algorithm. I emphasize slightly. The difference is quite subtle.

[Paul Sumi]

I've tried this, and you'll typically do slightly better increasing the resolution in Photoshop using the bicubic smoother algorithm. I emphasize slightly. The difference is quite subtle.

Dean, thanks for sharing your real world experience.  If I might ask, which raw converter are you using and which version of PhotoShop?

Paul

[DeanChriss]

Dean, thanks for sharing your real world experience.  If I might ask, which raw converter are you using and which version of PhotoShop?

Paul

I used Adobe Camera Raw (comes with PhotoShop) and PhotoShop CS3. Compared to Adobe Camera Raw, other raw converters might do a better or worse job of increasing the file resolution, but the bicubic smoother algorithm in PS seems to be quite good for enlarging files. Of course the amount of difference you'll see between any enlarging method or program will depend on how much you're increasing the file size. When I experimented with this I was starting with 17MP files and going to 20"x30" image at 360 dpi. Starting with 6MP printing something like 12"x18" is no problem and you can go quite a bit beyond that if everything is nice and sharp to start with -- or if it's an image where nothing has to be really sharp, like an abstract blurred landscape. If you're using an Epson printer you'll also do better to use 360 dpi (or even 720 dpi - which I believe is the native driver resolution) before printing. PhotoShop does a somewhat better job of ressing up than the Epson driver, though using 360 dpi seems to be more than adequate. Programs like Qimage do the ressing up to the native driver resolution for you before you print from them. Doing that in PS is a little more work but the result is the same.

[snickgrr]

In my not too stringent testing I found I got slightly better results from up-rezzing from my raw developer than I did through CS4.  I process through Iridient Raw Developer which uses Lanczos5 and Lanczos5 scaling algorithms.  Admittedly, the difference was subtle but no matter how I mixed up the prints I could always pick out up-rezzed from raw prints over the up-rezzed from PShop.  Just seemed more detail, better contrast, better sharpness.

[Ernst Dinkla]

So far I only see Photoshops's Bicubic as the ruler the other methods are measured with. There are applications with better extrapolation like Qimage, Irfanview, etc. Despite that it is very likely that there will be no answer what delivers the best image quality, Raw or cooked, Bicubic or Lanczos, etc. It is all very subjective if you follow the discussions on this subject and where an algorithm may  proof to be good at 3X, another one is preferred at 1.5X. Not to mention the content of the image that plays a role. See for example this discussion:

http://www.photokb.com/Uwe/Forum.aspx/phot...enuine-Fractals


met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/