Re: [Gimp-user] Another Gimp/UFRaw topic
On 2009-10-03, Norman Silverstone nor...@littletank.org wrote: What do you think are benefits of using jpegs with quality above 95%? I have absolutely no idea, it is just that I came across a reference somewhere which said I use 98% jpeg compression when archiving images. Better use compressed 8-bit sRGB TIFF instead (all minilabs I know would reject TIFF with *any* compression, though...). Why is that? Why is WHAT??? You need to Trim the posting more precisely... If you mean why TIFF?: Since TIFF provides no-artefacts storage at the same size as what you got from your JPEG (which WILL create artefacts). Why 8-bit? I already discussed that; and since your input is 8-bit, most probably you won't get any advantage from 16-bit. (Well, currently GIMP won't even produce 16-bit...) Why compressed? To save size... Puzzled, Ilya ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
Better use compressed 8-bit sRGB TIFF instead (all minilabs I know would reject TIFF with *any* compression, though...). Why is that? Why is WHAT??? You need to Trim the posting more precisely... I wonder if the questioner meant why do minilabs reject TIFF with *any* compression? Norman ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
On 2009-10-02, Norman Silverstone nor...@littletank.org wrote: I have been following this thread with interest so I decided to do some tests. The results may be relevant or not as the case may be but I think that they are interesting. My little camera gives a RAW image = 8.6 MB and a jpeg image = 2.6 MB. The developed RAW image from UFRaw saved at 98% jpeg = 17.2 MB What do you think are benefits of using jpegs with quality above 95%? Better use compressed 8-bit sRGB TIFF instead (all minilabs I know would reject TIFF with *any* compression, though...). Ilya ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
I have been following this thread with interest so I decided to do some tests. The results may be relevant or not as the case may be but I think that they are interesting. My little camera gives a RAW image = 8.6 MB and a jpeg image = 2.6 MB. The developed RAW image from UFRaw saved at 98% jpeg = 17.2 MB What do you think are benefits of using jpegs with quality above 95%? I have absolutely no idea, it is just that I came across a reference somewhere which said I use 98% jpeg compression when archiving images. Better use compressed 8-bit sRGB TIFF instead (all minilabs I know would reject TIFF with *any* compression, though...). Why is that? Norman ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
On Sat, 03 Oct 2009 08:59:11 +0100, Norman Silverstone wrote: I have absolutely no idea, it is just that I came across a reference somewhere which said I use 98% jpeg compression when archiving images. If you're archiving images that aren't compressed with lossy compression, use a format that stores them losslessly. If the images are already compressed with lossy compression (=JPEG), don't recompress them. -- Jernej Simončič http://eternallybored.org/ ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
Ok, I want to make sure that I've asked my question clear enough before I decide that you guys have blown me away with your technological knowledge. I'm shooting in RAW and so I'm opening up a RAW file with UFRaw because without opening the file first with UFRaw, I can't get it into into Gimp for Post Processing. I hope I'm right so far. Well, after opening the RAW file in UFRaw and whether I perforn any adjustments or not in UFRaw, if I hit OK to send it to Gimp isn't it still a RAW file when it's in GIMP or has UFRaw converted it to a jpg automatically and that is why the image looks crappy in GIMP, particulairly when zoomed in on? I have been following this thread with interest so I decided to do some tests. The results may be relevant or not as the case may be but I think that they are interesting. My little camera gives a RAW image = 8.6 MB and a jpeg image = 2.6 MB. The developed RAW image from UFRaw saved at 98% jpeg = 17.2 MB and then that image loaded into GIMP and saved as xcf = 17.0 MB. Norman ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
On 2009-09-30, Carusoswi for...@gimpusers.com wrote: In the spirit of the OP's question, if you make no adjustments in UFRAW, is there any more latitude for adjustment in the resultant JPG file (in Gimp or other editing application) than what you might get straight from the camera? This is not a very have-a-clear-answer topic. I would guess that with Canon, the answer is straightforward: the RAW-converted output would be SIGNIFICANTLY better than in-camera one in ALL respects. Dynamic range, handling of clipping, handling of noise, sharpness, etc. With cameras which use more advanced versions of the Apical Iridex hardware or firmware (starting with Sony, but Nikon is reported to be in process of catching up), the situation is not as clear. I did not see any report of RAW processor which can match Apical-style Dynamic Range Optimizations. So: there might be one respect (tonal mapping, sometimes called dynamic range) in which RAW-processed-JPEG might be not as good as in-camera one... It feels as though I have a lot of latitude in GIMP. 8-bit is good enough for minimally postprocessed images, since noise would provide sufficient dithering, both in highlights and in darks. However, significant noise reduction and/or substantial tonal mapping has a risk to make banding visible. Which makes GIMP not very suitable for such styles of photography. (Not so with the subjects I favor most, so I did not see that.) Hope this helps, Ilya ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
Ilya - Thanks for your earlier note -- I am quite happy to stand corrected and your post suggests a basic experiment I can easily do: compare in-camera processed and post-processed RAW images for the same scene and settings. I'll have a limited sample to work with: my only camera delivering RAW images is a Pentax K100D, quite dated now by newer technology. On the other hand, I can compare UFRaw into GIMP and Photoshop Elements with the Pentax plug-in into PSE and (if I have a suitable intermediate format) into GIMP. At the very least I'll learn something. If I see anything surprising or interesting I may share it and hopefully get useful feedback. Anyway, there's no substitute for knowing what one's own equipment does. On Thu, 1 Oct 2009, Ilya Zakharevich wrote: On 2009-09-30, Carusoswi for...@gimpusers.com wrote: In the spirit of the OP's question, if you make no adjustments in UFRAW, is there any more latitude for adjustment in the resultant JPG file (in Gimp or other editing application) than what you might get straight from the camera? This is not a very have-a-clear-answer topic. I would guess that with Canon, the answer is straightforward: the RAW-converted output would be SIGNIFICANTLY better than in-camera one in ALL respects. Dynamic range, handling of clipping, handling of noise, sharpness, etc. With cameras which use more advanced versions of the Apical Iridex hardware or firmware (starting with Sony, but Nikon is reported to be in process of catching up), the situation is not as clear. I did not see any report of RAW processor which can match Apical-style Dynamic Range Optimizations. So: there might be one respect (tonal mapping, sometimes called dynamic range) in which RAW-processed-JPEG might be not as good as in-camera one... I'm not sure I follow that, unless the sensor's bit-depth and that of the camera's RAW format are different. I'm not at the stage of getting full scale from my images: still working for consistent, decent quality prints from straight-forward subjects. - Mills ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
On Thu, 2009-10-01 at 07:11 -0700, Ok, I want to make sure that I've asked my question clear enough before I decide that you guys have blown me away with your technological knowledge. I'm shooting in RAW and so I'm opening up a RAW file with UFRaw because without opening the file first with UFRaw, I can't get it into into Gimp for Post Processing. I hope I'm right so far. Well, after opening the RAW file in UFRaw and whether I perforn any adjustments or not in UFRaw, if I hit OK to send it to Gimp isn't it still a RAW file when it's in GIMP or has UFRaw converted it to a jpg automatically and that is why the image looks crappy in GIMP, particulairly when zoomed in on? Well you would need to Sharpen the RAW image, JPG's are normally sharpened in camera but not so with RAW. In fact even most JPG images could benefit from some sharpening. Cheers George ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
On 2009-10-01, John Mills johnmi...@speakeasy.net wrote: With cameras which use more advanced versions of the Apical Iridex hardware or firmware (starting with Sony, but Nikon is reported to be in process of catching up), the situation is not as clear. I did not see any report of RAW processor which can match Apical-style Dynamic Range Optimizations. So: there might be one respect (tonal mapping, sometimes called dynamic range) in which RAW-processed-JPEG might be not as good as in-camera one... I'm not sure I follow that, unless the sensor's bit-depth and that of the camera's RAW format are different. Sensor bit-depth is an absolutely bogus metric (unless one uses it as an indicator of amount of RD, which may correlate with other, important issues; such as read noise and correlation of noise of nearby pixels). If RAW files were compressed to 8-bit gamma=2, they won't loose practically any information; 9-bit would be a significant overkill (assuming full-well about 70K electrons, as typical large-sensor dSLRs have). gamma=2.2 is very similar. (The special significance of quantization after gamma=2 is that Poisson noise becomes constant-width, thus dithers in dark parts as well as in highlights.) If you do not know what DRO is, look on dpreview, and/or look for examples on Apical site. Ilya ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
On 2009-10-01, Bryan for...@gimpusers.com wrote: Well, after opening the RAW file in UFRaw and whether I perforn any adjustments or not in UFRaw, if I hit OK to send it to Gimp isn't it still a RAW file when it's in GIMP or has UFRaw converted it to a jpg automatically and that is why the image looks crappy in GIMP, particulairly when zoomed in on? I have no idea how your communication channel is configured. I would use sRGB 8-bit TIFF (do not know whether deflation makes sense [called ZIP in GIMP]) with no downscale, or at most to-75% downscale (to-65% should be OK with most pocket cameras). Isn't there is only a relatively small amount of things you can do to an image in UFRaw? Probably true (never used UFRaw ;-). On the other hand, AFAIK, GIMP has practically no tools to do photo-related work either (one can't even apply a curve to L channel without going through a hundred hoops). Hope this helps, Ilya ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
Bryan - Wiser heads will probably correct or refine this, but ... The 'raw' file is supposed to represent data very close to what is provided by the camera's sensor array. Before saving images in non-raw formats (JPEG, etc.) the camera performs some conversions of the image field as well as - usually - applying some compression. These conversions are irreversible and represent a compromise intended to give pleasing images of common subjects. This is crudely analogous to the processing applied to color negatives by most photo processors as they are printed - you have probably seen the quite surprising results this sometimes gives: colors gone crazy! UFRaw gives you the chance to make different assumptions and adjustments, and keeps the original image file untouched in case you want another chance. It also provides as default a compensation similar to what the camera would have done if left to its own algorithms. That's what you get if you don't intervene. If you aren't making any adjustments in UFRaw you may be just as well-off to work with [say] JPEG images out of your camera. The intermediate stage of adjusting your image in UFRaw is one of the main reasons for using RAW format in the first place. At least that's my [mis?]understanding. - Mills On Wed, 30 Sep 2009, Bryan wrote: For starters, is there any good reason why UFRaw should be used for anything other than opening a RAW file before transporting it to Gimp? What I really wanted to ask was, Why, when open up an image in UFRaw and it looks great, even when zoomed in as much as allowed. However, when you sent it to Gimp via UFRaw, when you zoom into even a small amount the image is very pixelated. When or how did it become downsized or some sort of processing that might cause this to happen? Is it possible to bring in a RAW file and retain it's sharpness? Thanks for anyone's help in regards to this. ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Another Gimp/UFRaw topic
On 2009-09-30, John Mills johnmi...@speakeasy.net wrote: If you aren't making any adjustments in UFRaw you may be just as well-off to work with [say] JPEG images out of your camera. The intermediate stage of adjusting your image in UFRaw is one of the main reasons for using RAW format in the first place. This is as far from being true as one can get. A hint: a camera uses as-much-pessimized-as-possible computer, and does RAW--JPEG conversion in a fraction of a second. RAW converter most probably uses hundreds times more powerful hardware, and takes up to minute(s) to perform convertion. Guess how the results compare... Hope this helps, Ilya ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
