What do humans see?
The human eye is most sensitive for yellow-green light. Take a look at the next gradient for instance:
To me, indeed the green-to-yellow part looks brightest. Not so to Photoshop however.
About a hundred ways to loose the color
Your image just became 1/3 of the original size, and that weight loss is caused because there’s now only a ‘gray’ channel instead of a red, green and blue one.
Big drawback of this method, is that it’s destructive: You indeed loose the color: It’s gone for good. Since you also have zero control, I’d never use this method.
So, we want something that’s reversible. Lots of ways to do that, using (adjustment) layers, but not all of them good… Let’s start off by naming just about the worst way imaginable: Desaturate. What this does, is that it removes all color information from an image, without the option for any user intervention. While that may or may not be important to you, this should be: All colors are treated as if they were equal.
While equality is a great thing, in this case, it isn’t, since to us different colors aren’t equal. Read the rest of this entry »
How does it work?
Lightroom 2 has two kinds of sharpening: Capture sharpening and output sharpening. Capture sharpening is used to neutralize the blurring caused by the Anti Aliasing filter in your camera.
Output sharpening is dependent on output (print or screen, what size) and meant to overcome the softening caused by resizing or happening when printing.
Output sharpening in Lightroom is simple: You get 4 options when you export the image: Off, low, standard or high. All else is taken care of by Lightroom. Ease of use for sure. Drawback is that you cannot preview it, so you’ll need to experiment a bit. After that, it’s “set and forget”.
Capture sharpening on the other hand, requires a bit more user interaction. The settings will depend on camera used, subject and personal preference. You can preview it, but only at 100% or higher magnification. So you either need to zoom in, or you can view sharpening in the
microscopic small “preview window” Lightroom 2 has for this purpose.
(There is off course the workaround I mentioned in an earlier blog post)
The “Detail” Tab
…in Lightroom is where it’s at: You get 4 sliders for sharpening: Amount, Radius, Detail and Masking.
Some of these are quite self-explanatory if you know a bit about digital imaging, the others might be new to you. Read the rest of this entry »
And why they deceive you
Adobe Photoshop Lightroom, like many other Raw converters, has a clipping warning.
The purpose of it is to give you a visual warning (apart from the histogram) of what parts of an image might be clipping.
What is clipping?
A pixel is clipping when it reaches a value of 0 or 255 in one or more channels, and “should have gone further”. Since it cannot go lower then 0 or go higher then 255, it remains at those values: Detail is lost if one or two color channels clip, part of the image is solid black or white if all 3 channels clip.
The effect of color space
As with anything in digital imaging, the color space used has a big influence: A wide gamut color space (such as ProPhotoRGB) will have lower values for the same color then for instance sRGB. So a color that is clipping in sRGB, need not be clipping in ProPhotoRGB! Read the rest of this entry »
In the “analog” days, it used to be simple: You had a slide looking like you wanted, and that was a fixed reference point. So it was “somebody else’s problem” to make a print that matched the slide: WYSIWYG. Simple. Or at least: Not your responsibility. Negatives were a bit more complicated, but still: S.E.P.
Nowadays, you’ll have a file that looks good on your screen. Since you probably don’t want to lug your computer and monitor with you anytime you want to make a print, only to be able to show what you think the print should look like, how do you manage to get a print that looks like the image on your screen?
…of course, is “manage”. As in: Color manage: “Out of the box” every monitor will display an image different. Ever seen a store with 20 televisions in a row? All TVs looking different? Same will be the case with computer monitors if you don’t take countermeasures.
While the TVs pretty much boil down to “personal preference”, with digital imaging it’s about accuracy.
Read the rest of this entry »
How to see what you’ll get
for a web gallery.
Normally, Lightroom will only let you preview sharpening and noise reduction at 100% view. This is a good thing™ in my opinion, since it is capture sharpening, meant to negate the effects of an anti-aliasing filter in front of the sensor. You’d get all kinds of moiré without an AA filter, as can be seen in the hilarious story Eamon Hickey wrote about the NC2000.
Since the AA filter softens the image a bit, you need to sharpen it. This is input sharpening. So it should be judged at 100%. Unlike output sharpening, which is better judged at reduced size, at least: For print. For web view at 100% and WYSIWYG.
Or is it?
I recently was processing a few ISO 6400 images, which had severe noise in them. Here I ran into the problem that the NR isn’t shown at “fit window” view. So I had no way to judge what the images would look like online. Read the rest of this entry »
and LUT profiles
In my previous post, I wrote about Firefox 3.5 “better wait for version 3.5.1”
That version was released today, and I’m sorry to say, It still has its problems:
For one thing, it still doesn’t support ICC V4 profiles.
For another, by default it color manages like Safari does: Wonky: Only images with embedded profile are managed. So you could get problems as described on this page: The image looks different from the background.
On my Mac, it didn’t. What the heck? I hadn’t changed it from the default setting…
No matter what I set in the “gfx.color_management.mode”, it looked like the thing kept managing everything (except when setting “0” off course). No way to get the images on that page to look different from the background. “Here be dragons” indeed.
But wait, there’s more
The background looked different from the background of the same page opened in (fully colormanaged) Flock 2.5. In fact, the background looks like the page opened in Safari. Yet there was no change on the images with and without profile. Another “what the heck”? I’d already checked that images with embedded profile were color managed… Read the rest of this entry »
and color management
A lot of people are confused the first time they save an image for web display: The image looks different in a non color managed browser then it did in Lightroom or Photoshop. One “solution” was to view the image in Photoshop like it would appear in a non color managed application, by going View > Proof setup > Monitor RGB. This would show you how the image would look in a non color managed application on your screen. Still a guess what anybody else would see though, since you’re seeing the difference between the monitor profile and sRGB…
A much better option would be for everybody to browse color managed.
Up until recently, most browsers were not color managed. Safari changed that, and was the first color managed browser for PC. Internet Explorer had provided a color managed browser for Mac OSX before that, but it is discontinued now.
Read the rest of this entry »
part 2, not the best news
In my previous blog post about the subject, I mentioned a workaround for the bug, and also said I didn’t like the idea of converting to GenericRGB somewhere in the process since it might clip colors…
Gave it a quick try today, and yeah, it does clip “somewhat”…
Same image as last time. Original is AdobeRGB. In this image, some purples and dark blues are out of gamut for the R2880, using Epson Premium Glossy paper. Admittedly, not your “average” color palette, but one that does show problems if they are there.
Let’s start by showing the original converted to sRGB; Read the rest of this entry »
don’t seem to play nice together.
When testing my Epson R2880 on PSCS4, it was quite obvious that something was off; The print came out looking nothing like the softproof on screen.
To give an indication of what it looked like: Here is a splitscreen: Top left is the softproofed image, bottom right is what the print looked like:
(screenshot converted to sRGB for web display: The difference is bigger in print)
The same image printed from PSCS2 was a perfect match to the softproof. Very weird.
I remembered that another photographer had complained to me about similar issues, and showed me some pdf files in preview. (In OSX you can preview a print as pdf file in Preview).
So I tried that. What a surprise: pdf generated when printing from PSCS2 was entirely different from the one using PSCS4. Same printer driver, same settings in Photoshop, same everything.
Neither of the pdfs looked even remotely like the respective prints by the way. The PSCS4 pdf looked like the softproof (as did the PSCS2 print).
Getting weirder by the minute.
A search on the net only brought up a “Double profiling” issue in OSX 10.5.something. Not what I was experiencing. Also, I’m running 10.4.11.
So, I decided to investigate further.
The pdf generated when printing from PSCS2, has an AdobeRGB1998 profile embedded. No idea why, since it is obvious the wrong profile (should be the paper specific profile for the R2880 I’d think, but that also isn’t the case)
Even weirder, the PSCS4 pdf, had a GenericRGB profile. What? Why on earth… That one has an even slightly smaller gamut then sRGB as far as I know…
messing about testing with profiles followed.
It turned out that converting the PSCS2 pdf to GenericRGB, then assigning the paper profile, gave two identical images (easier to compare that way around, since the pdf coming out of the PSCS2 print path was very saturated and weird looking because of the wrong profile). Both were now again looking like the softproof in Photoshop.
So, doing the reverse (Convert to paper profile, assign GenericRGB) should give a decent print out of PSCS4. (at least, looking at the pdf. Haven’t wasted any paper on it yet).
So far for a workaround, now for the explanation…
Including “GenericRGB” in the search term proved to be a good idea. On the Adobe Forums I found a thread about grayscale printing (no wonder I hadn’t found it earlier).
In that thread Eric Chan explains how OSX Leopard will convert the image data to Generic Gray or Generic RGB before handing it off to the driver. So, yeah. That’s likely to screw things up…
I’m still not sure why or where the PDF out of PSCS2 gets an AdobeRGB profile. Seems rather silly if you ask me.
I might use the workaround when in PSCS4, or print from PSCS2 until this issue gets fixed… I think I’ll mostly use the latter, since I don’t like the idea of converting to GenericRGB somewhere in the process; it might clip colors without me having any control…
Have to compare a few prints, to see if there are differences.
Edit: The workaround does have its drawbacks: See my next blog post.
(Apple and Epson: Are you reading this?)
First blog post.
At least, on my own blog (to be).
I’ve commented a fair bit on other people’s blogs, when the subject was Colormanagement, and someone presented wrong facts. For instance if it was recommended to set Photoshop to use “Monitor color” as working space, since then anything would look the same in Photoshop and the (not color managed) browser. Color management just went right out the window, as well as any chance at consistency…
Therefore, I believe this to be *bad* advice, so often I’d comment something along those lines, or sent the poster an email. I can’t stand misinformation. I’m kinda funny that way.
Because I’m kinda funny in other ways as well, I also like to know how stuff works. (And if possible, also why)
That sometimes leads to hours of searching as to why something doesn’t work as expected, instead of just accepting the fact and get on with what you were doing… So probably not the best practice, both for your social life, and in the business kind of way. For the last, I couldn’t care less, and my social life is okay, thanks very much. Also, it
is satisfying my curiosity has the added advantage of getting to understand the problem better, which gives an advantage when you engage other (peoples) “irrational” problems.
So, what to expect here then?
I have no idea yet. I don’t even know if it’s going to be a regularly updated blog, or more “website-like, static” approach. I’m not completely without a clue however:
First, I plan to post a few simple posts on the “how and why” of color management. Just to cover the basics. I’ve posted the same (or similar) on POTN.
Incidentally, that forum is probably what inspired me to start all this: I started a thread there a few years back about color problems. Due to my lack of organisation, limited knowledge at the time (and not locking the thread), it became what was lately accurately referred to, a “Huge meandering thread”. This blog is my penance, and an effort to bring some order to that chaos.
Later on (when I get comfortable with blogging), I’ll probably also post solutions whenever I encounter a problem (For instance: PSCS4 seems to have a bug regarding color managed printing, looking in to that as I have time to spare, I’m using PSCS2 until then)
I sincerely hope that later posts gain in structure compared to this one, and also are a bit more relevant. But this is at least better then the default “Welcome” post by WordPress… (And there’s no-one around to see it anyway).