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  #1  
06-19-2011, 03:01 AM
manthing manthing is offline
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Look at the attached picture. originally it was a black&white picture. but it seemed to have a tinge of some colour. so i desaturated the picture which helped. but there still remained a bit of green as can be seen in the attachment.

i've tried:
- desature
- hue/saturation with the saturation slider all the way down
- gradient map

and i've tried using all 3 one after the other. nothing seems to work. the green is still there.
any ideas why that is happening? and how to remove it?

i suppose i could do a colour replacement. or perhaps some copying & pasting or spot healing etc. but it would be nice to know why photoshop's desaturate fails to remove this colour.

thanks.
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Someday, 12:01 PM
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  #2  
06-19-2011, 11:48 AM
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No photo is attached.

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  #3  
06-19-2011, 12:06 PM
manthing manthing is offline
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Sorry, must have been an invalid file first time around.


Attached Images
File Type: jpg pic1.JPG (7.2 KB, 7 downloads)
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  #4  
06-19-2011, 02:41 PM
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The attached image is completely grayscaled -- no color whatsoever.

This means your computer monitor is lacking in quality. For example, when an image has a green tint on a non-RGB CRT monitor, it generally implies that the luminance (Y) is overpowering the chrominance (Cr + Cb). Luminance in a color YUV signal also contains the green portion of the image. The chroma channels carry the red and blue, and at half-scaled sizes. Hence 4:2:2. This also applies to video input devices, such as DVD player. Certain latter-model LiteOn (and iLo clone) DVD recorders, for example, were infamous for playing and recording "green tinted video". An undesirable effect, to be sure!

The tint problems can be inherent to the monitor, as well as caused by graphics cards, video cards, video chipsets in standalone players, or even inferior cables. So you problem could be a bad wire, bad graphics card, or even a bad LCD (or CRT, etc). It can also be caused by the monitor color settings (gamma), or even the colorspace being used by the computer (sRGB vs others). You can drill down even further, and have software-based changes in color -- AdobeRGB vs sRGB, for example, for the calibration settings within Photoshop.

On a high-quality IPS based flat LCD panel, the attached image is perfectly black, white, and shades of gray. Zero colors, zero tints.

If you do a lot of graphics, video or image work, you really should use color-accurate IPS LCD monitors. For example:

In USA:
- ViewSonic 23" IPS LCD @ B&H, $285 - http://www.bhphotovideo.com/c/produc...3167/KBID/4166
- HP 22" IPS LCD @ B&H, $265 - http://www.bhphotovideo.com/c/produc...3167/KBID/4166
- HP 30" IPS LCD @ B&H, $1200 - http://www.bhphotovideo.com/c/produc...3167/KBID/4166
- ViewSonic 26" IPS LCD @ B&H, $880 - http://www.bhphotovideo.com/c/produc...3167/KBID/4166
- Amazon.com also has IPS LCD monitors, though B&H is my preferred vendor for this specific kind of item, and prices seem to be better.

In UK / Europe:
- LG 23" S-IPS @ Amazon.co.uk, 155 - http://www.amazon.co.uk/gp/product/B...SIN=B004GV9ADW
- LG 30" S-IPS @ Amazon.co.uk, 855 - http://www.amazon.co.uk/gp/product/B...SIN=B0015LWB00
- Dell 23" IPS @ Amazon.co.uk, 220 - http://www.amazon.co.uk/gp/product/B...SIN=B003R7K332

LG is easily the best of the IPS monitors, in terms of color accuracy, and features somewhat more advanced "S-IPS" technology.
Viewsonic makes for a nice runner-up maker of IPS monitors, along with other brands like HP, NEC and Dell.

There's also Eizo and Lacie brands. Eizo is a fan favorite in the photo community, though it seems overpriced to me, especially compared against a good LG S-IPS LCD. And then Lacie is not a manufacturer, but simply a private-label brand, and I'm not readily aware of what brand of monitor is actually "under the hood". Yes, Eizo and Lacie sell good stuff that works, but you pay for the brand name as much as for the item itself. While cash-rich photographers will tell you to use Eizo, us normal folks can make out quite nicely with LG and ViewSonic, getting the same performance at a fraction of the cost.

When it comes to images being too dark, uneven, full of red tint, blue tint, yellow tint, green tint, purple tint, etc, it's quite often a problem with the monitor technology. A TN based (non-IPS) LCD is great for average users with video games, movie watching, email, typing in Word, etc -- but when you're wanting to do serious graphics/image/video work, you'll benefit quite a bit from an IPS panel.

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  #5  
06-19-2011, 03:20 PM
manthing manthing is offline
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ahh, i see.

i have an oldish iiyama vision master pro 454 crt monitor.

the color temperature was on 65K.
i have now raised it to 100k and then used a free monitor calibration software to adjust things.

the picture does seem to have lost its green tinge now.

but the monitor seems a touch blueish at color 100K setting.

it will do for now.

but i take your point about getting a good IPS LCD monitor.
i will look into it and upgrade in due course.

thanks for your help.
invaluable as always.
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  #6  
06-19-2011, 03:24 PM
manthing manthing is offline
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along the same lines, are the dell ultrasharp (eg u2711, u3011 etc) monitors as hot as some reviewers say they are?
just curious as these are outside my budget range.
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06-19-2011, 03:48 PM
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Is a Dell LCD best? Not in my opinion, no.

I've not tested these specific monitors, but I will say this:
Dell generally suffers from what I'd call "stupid consumer syndrome" -- providing what is demanded rather than what is truly best. When it comes to LCD monitors, too many companies create overly bright eyeball-scorching LCDs, because people are impressed by "bright colorful images" in stores. Nevermind that it cooks the image quality, harms your eyes, and is inaccurate color rendition. The best monitors are the so-called "dim" displays. (Dim ONLY when compared to the insanely overbright LCDs.) Dell is a habitual offender when it comes to big bright displays.

The UltraSharp is also less than sharp, according to complaints about the anti-glare coating making text hard to read. LCD is inherently sharp technology, because individual pixels are illuminated. (The gimmicky name "UltraSharp" somewhat irritates me because it insinuates other LCD monitors are not sharp, which is ridiculous.) The only way to make a blurry LCD is to use crappy glass for the screen, add coatings that detract from the sharpness, etc.

Dude, skip the Dell. Get an LG.

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  #8  
06-19-2011, 03:53 PM
manthing manthing is offline
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post #5 - i must be mistaken. the previous color temperature was something other than 65K but not sure what it was.

i did increase the color temperature to 100K.
but after reading up a bit, i changed it to 65K and then ran a software monitor calibrator.

so now things seem a bit yellowish.
and the picture does look black, white & gray.

again, for now, it will suffice.
i'll get an IPS LCD monitor soon.
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  #9  
06-19-2011, 03:54 PM
manthing manthing is offline
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post #7 re dells - gotcha. ta.
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  #10  
06-19-2011, 03:56 PM
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Some of this may explain the color issues I've noticed on some of your colorization work in the past.
Blues vs purples, blues vs greens, etc. The color you stated wasn't always the color it was. At least not on my LG S-IPS.

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  #11  
06-19-2011, 04:05 PM
manthing manthing is offline
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yes, i was just looking over some of my recoloring work.
quite surprised they still look quite ok/good!
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