If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
"Assigning" vs. "Matching" a color profile
On Thu, 31 Dec 2009 09:42:28 -0800, isw wrote:
The scanner came with a profile that I have no reason to doubt, and all the images in question were scanned using it. It's just that iPhoto gets indigestion when trying to handle images bearing that particular profile -- and I have no idea why, and no way to find out (the scanner maker is no longer around). My "solution" is to move the images to a different profile, and right now I'm trying to figure out what one would be "best". So the simple solution as has been been proposed is to simply save the original scanned images for future use, and convert to aRGB for your present use. Problem solved, the future and cuurent problems need ot be solved in a single file. I really doubt the issue with iPhoto will be a problem in the future. Ohtherwise why not deal with Apple support on this issue if it is indeed a valid profile? |
#22
|
|||
|
|||
"Assigning" vs. "Matching" a color profile
On Mon, 28 Dec 2009 11:11:08 -0800, isw wrote:
This is on a Mac, BTW. I have a large number of scanned slides bearing a color profile (assigned by the scanner) that gives iPhoto fits; I'd like to change it. Using ColorSync, I can "assign" a different profile, or I can "match" to a different profile, but I do not understand which I should do, or (more importantly) what the difference is between the two. Further, I don't know which profile I should move to: "Generic RGB"; "sRGB"; or what? The images are my own, and will not be displayed on the web. I'd like to keep them at the highest possible "accuracy" (whatever that means). A whole lot of googling has produced many descriptions of *how* to do these things, but nothing on *why* or *which*. Can anybody shed some light, please? Isaac I think you will find that the article at http://www.adobe.com/digitalimag/pdf...p_colspace.pdf will help you unravel your problem. Eric Stevens |
#23
|
|||
|
|||
"Assigning" vs. "Matching" a color profile
On Thu, 31 Dec 2009 09:42:28 -0800, isw wrote:
In article , me wrote: On Mon, 28 Dec 2009 11:11:08 -0800, isw wrote: This is on a Mac, BTW. I have a large number of scanned slides bearing a color profile (assigned by the scanner) that gives iPhoto fits; I'd like to change it. Using ColorSync, I can "assign" a different profile, or I can "match" to a different profile, but I do not understand which I should do, or (more importantly) what the difference is between the two. Further, I don't know which profile I should move to: "Generic RGB"; "sRGB"; or what? The images are my own, and will not be displayed on the web. I'd like to keep them at the highest possible "accuracy" (whatever that means). A whole lot of googling has produced many descriptions of *how* to do these things, but nothing on *why* or *which*. Can anybody shed some light, please? Have you tried using a utility such as http://www2.chromix.com/ColorSmarts/...sion=SessID:62 A682011e0e5088D5TII3F64BF5 to "correct" the scanner profile and then re-assgn the corrected profile to an image? The scanner came with a profile that I have no reason to doubt, and all the images in question were scanned using it. It's just that iPhoto gets indigestion when trying to handle images bearing that particular profile -- and I have no idea why, and no way to find out (the scanner maker is no longer around). My "solution" is to move the images to a different profile, and right now I'm trying to figure out what one would be "best". One possibility is that, being old, your scanner uses a now non-standard form of profile which iPhoto cannot recognise. Either that or the files produced by your scanner have a non-standard form of header. How do you scan - directly with the scanner or indirectly via an application using a Twain driver? Eric Stevens |
#24
|
|||
|
|||
"Assigning" vs. "Matching" a color profile
On Fri, 01 Jan 2010 11:00:20 +1300, Eric Stevens
wrote: One possibility is that, being old, your scanner uses a now non-standard form of profile which iPhoto cannot recognise. Either that or the files produced by your scanner have a non-standard form of header. If you loked, I all ready pointed him to a util which might correct such a problem. "Have you tried using a utility such as http://www2.chromix.com/ColorSmarts/...88D5TII3F64BF5 to "correct" the scanner profile and then re-assgn the corrected profile to an image?" |
#25
|
|||
|
|||
"Assigning" vs. "Matching" a color profile
"isw" wrote in message
]... 1) Images on Kodachrome originals *may* (depending on the subject matter) have a wider gamut than sRGB can handle, and You still need to consider the scanner's gamut. The hardware itself might not be up to recording the 'Chrome's full glory; cramming it through the scanner's profile will already have lost some of the raw information; and each subsequent remapping will lose still more. If you really want to worry yourself sick, the 'Chrome itself is an imperfect image of the original scene. I read elsewhere you were using the manufacturer's supplied profile, and I wonder if I should even bring this up. It's better than nothing, of course, and by itself is probably sufficient to minimize unintended color casts. MonacoEZColor came with my Epson. It uses IT8 calibration targets, one for transparencies and another for reflective, to build device specific profiles. The differences between the stock profile and the custom profile were rather significant. Switching from one to the other, there were distinct color pops across the entire image, but none I would consider large or damaging. For that matter, I use X-Rite ColorChecker to profile my camera sensors. There's nothing really wrong with the images as they come out of the camera, but I find image fidelity improves with the custom profile. Just this afternoon, because it's still fresh on my mind, I grabbed a quick shot of soft sunlight caressing a bottle of Hoppe's oil sitting on the window sill. Before applying the camera profile, the bottle was rendered almost a dull red rather than Hoppe orange. You could almost feel the texture of the plastic in your hands looking at it onscreen. (Printing is a whole another exercise in anality. It's also better to not ask about the monitors and their calibration.) Again, there's nothing at all wrong with the images that come of the camera, even without profiling the sensor. It's the exact same situation as your stock scanner profile compared to a custom, measured profile. You wouldn't normally even think about it to complain, but once you start down this road, everything becomes a mess of profiling and obsessive white balancing and pixel peeping. You should know upfront where this is taking you. |
#26
|
|||
|
|||
"Assigning" vs. "Matching" a color profile
In article ,
Eric Stevens wrote: On Thu, 31 Dec 2009 09:42:28 -0800, isw wrote: In article , me wrote: On Mon, 28 Dec 2009 11:11:08 -0800, isw wrote: This is on a Mac, BTW. I have a large number of scanned slides bearing a color profile (assigned by the scanner) that gives iPhoto fits; I'd like to change it. Using ColorSync, I can "assign" a different profile, or I can "match" to a different profile, but I do not understand which I should do, or (more importantly) what the difference is between the two. Further, I don't know which profile I should move to: "Generic RGB"; "sRGB"; or what? The images are my own, and will not be displayed on the web. I'd like to keep them at the highest possible "accuracy" (whatever that means). A whole lot of googling has produced many descriptions of *how* to do these things, but nothing on *why* or *which*. Can anybody shed some light, please? Have you tried using a utility such as http://www2.chromix.com/ColorSmarts/...session=SessID :62 A682011e0e5088D5TII3F64BF5 to "correct" the scanner profile and then re-assgn the corrected profile to an image? The scanner came with a profile that I have no reason to doubt, and all the images in question were scanned using it. It's just that iPhoto gets indigestion when trying to handle images bearing that particular profile -- and I have no idea why, and no way to find out (the scanner maker is no longer around). My "solution" is to move the images to a different profile, and right now I'm trying to figure out what one would be "best". One possibility is that, being old, your scanner uses a now non-standard form of profile which iPhoto cannot recognise. Either that or the files produced by your scanner have a non-standard form of header. How do you scan - directly with the scanner or indirectly via an application using a Twain driver? Microtek never (to my knowledge) provided TWAIN drivers for the scanner I have (on OS X). I tried VueScan, but it and the scanner didn't get along well together. Makes me wonder if Microtek just didn't want anybody else to talk to their stuff. OTOH, I really have no complaints about ScanWizard (the scanner app Microtek provided). Isaac |
#27
|
|||
|
|||
"Assigning" vs. "Matching" a color profile
In article ,
me wrote: On Fri, 01 Jan 2010 11:00:20 +1300, Eric Stevens wrote: One possibility is that, being old, your scanner uses a now non-standard form of profile which iPhoto cannot recognise. Either that or the files produced by your scanner have a non-standard form of header. If you loked, I all ready pointed him to a util which might correct such a problem. "Have you tried using a utility such as http://www2.chromix.com/ColorSmarts/...sion=SessID:62 A682011e0e5088D5TII3F64BF5 to "correct" the scanner profile and then re-assgn the corrected profile to an image?" ColorSync Utility honors the Microtek profile without complaint, as does Preview, and Photoshop Elements, and Photoshop 7 (back when I was using Tiger), and GIMP. ColorSync Utility's "verify" function thinks it's fine. Both ColorSync utility and Preview are able to assign the Microtek profile to images in the same way they will assign any other profile. The app you pointed to doesn't look like it does anything useful in that context. Isaac |
#28
|
|||
|
|||
"Assigning" vs. "Matching" a color profile
In article ,
me wrote: On Thu, 31 Dec 2009 09:42:28 -0800, isw wrote: The scanner came with a profile that I have no reason to doubt, and all the images in question were scanned using it. It's just that iPhoto gets indigestion when trying to handle images bearing that particular profile -- and I have no idea why, and no way to find out (the scanner maker is no longer around). My "solution" is to move the images to a different profile, and right now I'm trying to figure out what one would be "best". So the simple solution as has been been proposed is to simply save the original scanned images for future use, and convert to aRGB for your present use. Problem solved, the future and cuurent problems need ot be solved in a single file. I really doubt the issue with iPhoto will be a problem in the future. Ohtherwise why not deal with Apple support on this issue if it is indeed a valid profile? Now that I understand the color profile "situation" a whole lot better than I did two weeks ago, I agree with your suggestion. the Adobe98 profile does seem to be the best choice -- sRGB would *possibly* reduce the gamut on some of the images, and ProPhoto would necessitate a move to 16-bit color values, something I have no intention of doing. But it took me a while to get to this point, and some of the information posted here was very valuable input to my decision-making process. It is a foible of mine, that I do not feel comfortable doing a thing merely because an "expert" (who may or may not actually qualify for that title) says to do it. It is necessary for me to understand *why* that is the proper thing to do. Happy New Year to all Isaac |
#29
|
|||
|
|||
"Assigning" vs. "Matching" a color profile
In article ,
Eric Stevens wrote: On Mon, 28 Dec 2009 11:11:08 -0800, isw wrote: This is on a Mac, BTW. I have a large number of scanned slides bearing a color profile (assigned by the scanner) that gives iPhoto fits; I'd like to change it. Using ColorSync, I can "assign" a different profile, or I can "match" to a different profile, but I do not understand which I should do, or (more importantly) what the difference is between the two. Further, I don't know which profile I should move to: "Generic RGB"; "sRGB"; or what? The images are my own, and will not be displayed on the web. I'd like to keep them at the highest possible "accuracy" (whatever that means). A whole lot of googling has produced many descriptions of *how* to do these things, but nothing on *why* or *which*. Can anybody shed some light, please? Isaac I think you will find that the article at http://www.adobe.com/digitalimag/pdf...p_colspace.pdf will help you unravel your problem. There is indeed a good deal of useful information in there. Had I come across it earlier in my investigation, things would have resolved considerably faster. As it is, it reaffirms a lot of what I've learned "the hard way", but that extra confirmation is always a good thing. Thank you. Isaac |
#30
|
|||
|
|||
"Assigning" vs. "Matching" a color profile
isw wrote:
What I "get" is: 1) Images on Kodachrome originals *may* (depending on the subject matter) have a wider gamut than sRGB can handle, and 2) I have no intention of measuring, one-by-one, nearly three thousand slides, to find out which ones in fact hold images needing that wider gamut and which do not, so 3) What makes sense to me is to handle all the images alike, and in such a way that minimal information is lost *no matter the content*. First: calibrate your scanner. You'll need an IT8 Kodachrome Target (google!) for your scanner. Otherwise, you're loosing information right away at the scanner. Then, save the raw data from the scanner with the ICC profile from your scanner calibration. That way, you can decide in 10 years you want to do something different --- and you can start again right at the point the data came into your computer. That way, you loose no information past the scanning process. If you want to have 'final' images (alongside the above named RAWs!), it depends on what you want to do with them: "display on the web" or "consumer photo developing", sRGB and JPEG is the way to go. So far, my understanding is that sRGB *may* cause a (content-dependent) loss of gamut vis-a-vis Kodachrome, and that ProPhoto can handle it easily, but is probably too large a gamut unless I'm willing to commit to doing everything to 16 bit precision (which I'm not). Why not?? After all, your primary task is 'loose minimal information', not 'stay in 8 bit and save disk space', isn't it? So Adobe98 is my current "best guess" as to what I should convert these images to. Not really. The best guess is writing a small program that sees if you loose information *for this given image* at a list of colour spaces (sorted by size) and choose the colour space and bit depth that looses none --- then run that over all your images and let your computer do the work. Don't forget to attach the correct colourspace to your images. Now I need to figure out the least labor-intensive way to do that, have a program do the work, see above. and why two methods, both provided by Apple, produce visibly different results. They shouldn't produce visibly different results outside minimal adaptions for the colour space ... you might be doing something wrong. Maybe as easy as converting to Adobe RGB, but not attaching that information to the image, so it gets shown as sRGB (and looks somewhat washed out). -Wolfgang |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
"Corset-Boi" Bob "Lionel Lauer" Larter has grown a "pair" and returned to AUK................ | \The Great One\ | Digital Photography | 0 | July 14th 09 12:04 AM |
Album 26 Special "January 2008-3" "Lumières d'Opale" | Lumières d'Opale | Photographing Nature | 0 | February 7th 08 12:32 PM |
Album 24 Special "January 2008-1" "Lumières d'Opale" | Lumières d'Opale | Fine Art, Framing and Display | 0 | January 8th 08 05:20 PM |
How to insert the "modified time" attribute in "date taken" attrib in batch mode | ashjas | Digital Photography | 4 | November 8th 06 09:00 PM |