Max Alfy Posted August 20, 2009 Share #1 Posted August 20, 2009 Advertisement (gone after registration) I was surprised by the poor quality of one 900x600 BW photo on this forum: poor definition, strong JPEG artefacts. In fact the photo was registered as 8 bit RGB and weighed a mere 80 K (“Low” on PS Save as JPEG). I am sure the photo would have been much more appealing if it would have been (in that order): - converted to Grayscale after BW conversion (originally was a color neg) - gone through appropriate Levels/Curves/Sharpen - saved as Maximum quality JPEG (around 200 K) which is top for a pic of that size. My 2 cents… Link to post Share on other sites More sharing options...
Advertisement Posted August 20, 2009 Posted August 20, 2009 Hi Max Alfy, Take a look here JPEG BW quality on the forum. I'm sure you'll find what you were looking for!
bill Posted August 20, 2009 Share #2 Posted August 20, 2009 Let me get this straight... you entitle the thread "...quality on the forum" and are referring to one specific image? Have you thought of giving the individual who posted it the benefit of your expertise via a PM? Regards, Bill Link to post Share on other sites More sharing options...
Max Alfy Posted August 20, 2009 Author Share #3 Posted August 20, 2009 Good point Bill, I did not want to expose this critique for everyone to see, but did not think of a PM. On the other hand, basics reminders do no harm and may help some, me included. Link to post Share on other sites More sharing options...
bill Posted August 20, 2009 Share #4 Posted August 20, 2009 Good point Bill, I did not want to expose this critique for everyone to see, but did not think of a PM. On the other hand, basics reminders do no harm and may help some, me included. Fair enough. It didn't read as if you were trying to have a go at someone, but you can't guarantee that they will read your thread and realise it refers to them. Pop them a PM - I am sure that they will take it in the spirit it is meant. Regards, Bill Link to post Share on other sites More sharing options...
Cirrus1 Posted August 20, 2009 Share #5 Posted August 20, 2009 I want to chime in on this..... I have shot raw my whole digital life. I now like the BW jpeg output of the Leicas so much that I am migrating to jpeg only. I have some questions though. When in PS, if I covert to 16 bit and then go to greyscale it looks as if I lose a lot of detail( the histogram becomes really thin) so I have just been leaving them as rgb to do any levels or curves(frankly, I like what comes out of the d-lux 4 so much I hesitate to touch it). I have just been leaving them as rgb because I use quadtone rip to print and it doesn't "see" rgb. Is this the wrong approach? Thanks, John Link to post Share on other sites More sharing options...
JHAG Posted August 21, 2009 Share #6 Posted August 21, 2009 In any case, never use the "Save for Web & Devices" command in CS3 or CS4. It's squashing colors, flatten contrasts, generally "lighten" and "cleans" the image to the point of watering it down and greying the B/W. I convert to JPEG from 16 bits TIFF through 8 bits and retain most (not all) of the original values to post it on the Web. Link to post Share on other sites More sharing options...
stunsworth Posted August 21, 2009 Share #7 Posted August 21, 2009 Advertisement (gone after registration) I use save for web all the time and can't say I've noticed the problems you mention. Are you sure you're not seeing a colour space problem - you can specify sRGB as the output colour space when using save for web, but if that isn't selected and your working space is say Adobe 98 or ProPhoto, then you'll see problems similar to the ones you describe. Link to post Share on other sites More sharing options...
JHAG Posted August 21, 2009 Share #8 Posted August 21, 2009 I'm always in sRGB and had to considerably boost gamma, contrasts, highlights and shadows to retain something more or less approaching my original, never satisfactorily. Now I never use it. I possibly missed something, but am so pleased with the results I'm having now I don't feel the need to look back. Maybe I'm wrong. Link to post Share on other sites More sharing options...
stunsworth Posted August 21, 2009 Share #9 Posted August 21, 2009 A picture tells a 1000 words as they say. Here's the same image, saved first using the 'save' option, and the second using 'save for web'. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/93898-jpeg-bw-quality-on-the-forum/?do=findComment&comment=1000774'>More sharing options...
JHAG Posted August 21, 2009 Share #10 Posted August 21, 2009 In this case, # 2 is much lighter and contrasts in interesting zones (umbrella, dress, hair of the mannequin) are,as I said, slightly watered down. Details and micro-contrasts in embroidery are weaker. Meanwhile, reds (the plastic boxes) are clearer and compartments ridges less defined. In darker zones, light might be more pleasant in # 2, but I' prefer work from # 1 and proceed with local touch. I opened both pictures side by side and compared. Link to post Share on other sites More sharing options...
roguewave Posted August 21, 2009 Share #11 Posted August 21, 2009 In this case, # 2 is much lighter and contrasts in interesting zones (umbrella, dress, hair of the mannequin) are,as I said, slightly watered down.Details and micro-contrasts in embroidery are weaker. Meanwhile, reds (the plastic boxes) are clearer and compartments ridges less defined. In darker zones, light might be more pleasant in # 2, but I' prefer work from # 1 and proceed with local touch. I opened both pictures side by side and compared. I don't see that on my monitor. I'm fully calibrated on my 30" monitor at 2560 x 1600 pixels. I placed each picture in different parts of the screen & still no discernible difference for me. I save to sRGP with an action & when I look at the original 60MB file, it's undifferentiated from the 235K file I get from that action, thanks to William Palank Link to post Share on other sites More sharing options...
JHAG Posted August 21, 2009 Share #12 Posted August 21, 2009 Funny and interesting. You're speaking about a 60 Mb and a 231 Kb files. I suppose these are yours and not the two files we have here. I see discernable differences between these two images on both screens I have here. Both are calibrated too. What am I missing ? Link to post Share on other sites More sharing options...
stunsworth Posted August 21, 2009 Share #13 Posted August 21, 2009 I see discernable differences between these two images on both screens I have here. I've tried loading both images into Photoshop as separate layers in the same composite image. When I set the top layer's blend mode to 'difference' I get a black image on the screen, indicating to me that there are no major differences between the two images. Moving the cursor around gives some very small differences in the RGB channels, but the values are so small that I can't believe they could be seen as differences to the naked eye, and are more likely to be due to differences in Jpeg compression IMHO as the two images aren't identical in size. Link to post Share on other sites More sharing options...
JHAG Posted August 21, 2009 Share #14 Posted August 21, 2009 Steve, Really confusing. To my eye (I made the chromatic test some months ago here and had a result of 4 or 6 I believe, so I guess I see things more or less as they are ), #2 viewed in this site's window and not in CS3, is overall darker and has more density (distinctly so in the areas previously mentioned). Am I the only Doctor Spock to see this ? Link to post Share on other sites More sharing options...
Jamie Roberts Posted August 21, 2009 Share #15 Posted August 21, 2009 Steve,Really confusing. To my eye (I made the chromatic test some months ago here and had a result of 4 or 6 I believe, so I guess I see things more or less as they are ), #2 viewed in this site's window and not in CS3, is overall darker and has more density (distinctly so in the areas previously mentioned). Am I the only Doctor Spock to see this ? Yes you are The images are exactly, precisely, the same... if you can view untagged sRGB documents as sRGB documents What's maybe happening is the SFW version has no colour profile associated with it (which is the default, and good practice for Web browsers). The normal PS one does have an sRGB profile attached to it (this is according to BreezeBrowser and PS). I suspect that's all the difference in the world... I can't be sure, but you must be using a colour-aware browser that is not handling untagged sRGB documents very well. That's my only conclusion... without knowing what system you're on, how you're calibrated and profiled, and what browser you use (and how its set up) it'll be difficult to diagnose further. But this also means that most of the images you see on the Web are also not rendering correctly! Sorry! Link to post Share on other sites More sharing options...
JHAG Posted August 21, 2009 Share #16 Posted August 21, 2009 This is odd. These differences between a file (DNG, TIGG of JPEG) processed through "Save for Web & Devices" or through "Save" were noticeable on my PowerMac G5 Apple CInema Display, on my iMac 2008 and my 2 PowerBooks in CS3. They are also noticeable under Firefox and Safari, my two browers. For instance, mannequin's face here is visibly darker in #1. Red box beside the man is visibly more vermilion in #1 and more oxblood in #1. On 4 differents screens. Instead, when I check some of my pictures on the Eizo 30" screen of the web designer who is currently creating my website, the pictures he views on his screen have exactly the same values as on my screen, if better defined, due to the difference of quality of the Eizo (no such gap as the one I see here). Link to post Share on other sites More sharing options...
rob_x2004 Posted August 21, 2009 Share #17 Posted August 21, 2009 What are you guys discussing? Steves images? Theres an enormous difference between them, even on my iMac. Link to post Share on other sites More sharing options...
JHAG Posted August 21, 2009 Share #18 Posted August 21, 2009 What are you guys discussing? Steves images? Theres an enormous difference between them, even on my iMac. Finally, I'm not the only Spock here… Link to post Share on other sites More sharing options...
stunsworth Posted August 21, 2009 Share #19 Posted August 21, 2009 What's maybe happening is the SFW version has no colour profile associated with it (which is the default, and good practice for Web browsers)... Correct. Here's a version where I've used the 'save as' command, but without the embedded colour profile. This looks identical to the other two on my screen calibrated 24" iMac running Firefox. I've also looked at them using Safari, and all three look the same... Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/93898-jpeg-bw-quality-on-the-forum/?do=findComment&comment=1001100'>More sharing options...
rob_x2004 Posted August 21, 2009 Share #20 Posted August 21, 2009 Maybe its your room lighting Steve, or firefox, or the way youve set up your iMac. Anyway its the net. You never know what people see when they are looking at your images. There have been some horror stories that people have said lovely tonal range wonderful this that and the other. You have to assume people genuinely cant see it. Ah, but thinking back you had some images that the post processing was really obvious on my screens. Contrasts between areas youd tried to brighten to lift from the background were all over the shop, and the margins really obvious. Looking at the first two images that you say are exactly the same goes quite a long way to explain this. Ben is in a similar boat on my screens. Some of his edits are really obvious. Link to post Share on other sites More sharing options...
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