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Author Topic: Softproofing and rendering intent  (Read 5771 times)

CynthiaM

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Softproofing and rendering intent
« on: September 02, 2007, 09:06:20 am »

Recently, I started to soft proof when I noticed a loss of shadow detail, particularly on matte papers.  The soft proof adjustments have made all of the difference.  I've noticed when clicking in and out of various paper profiles in the soft proof dialog window, that some profiles make a big jump in brightness/darkness and sometimes in color with hue shift and or saturation.  And then there are some where you barely notice a difference.

Right now I am working on a file that is very high key, not a lot of color and not a lot of shadow detail.  I've noticed that with this type of image,  if I try the absolute rendering intent that there is a minimal shift between the Photoshop colorspace and the paper profile soft proof color space (when you ctrl, Y or command Y to turn the proof on and off).  Yet I've always read that the perceptual and relative rendering intents are preferable.

So what is advised in this instance?  Stick with the absolute rendering intent and be happy that I don't end up with umpteen soft proof layers and make sure to pick it in the print dialog or stay with perceptual or relative?

Thanks for your thought and comments.
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Scott Martin

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Softproofing and rendering intent
« Reply #1 on: September 02, 2007, 10:03:44 am »

The short answer is to soft proof with the same intent you will be printing with. If you print with perceptual (typically the preferred intent with most desktop printers and profiles), you should soft proof with perceptual. Of course could also use soft proofing to determine what intent to print with. There are complications with accurate black ink and paper simulation so while some people use them most people don't. If soft proofing isn't matching your printing (which is common) then you should reconsider the method and target settings with which the display was calibrated. There are lots of minutiae to discuss but that's a general overview.
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jjlphoto

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Softproofing and rendering intent
« Reply #2 on: September 02, 2007, 10:45:26 am »

Absolute is designed for mainkg cross-rendered CMYK proofs where you want to see actual tone in the 255 highlights rather than paper base. I'd avoid it for standard inkjet printing. Saturated is best suited for sign/banner graphic makers. That leaves Relative and Perceptual for most standard inkjet output for photos on paper.

The difference between Relative and Perceptual is on how they handle taking the large image gamut and fitting it into the small printing gamut. Relative basically whacks off out of gamut colors, where-as Perceptual tries to retain as many original colors as possible and as a result, the mid-pint of the image may shift as Perceptual is squishing and rotating that large original gamut to fit into the smaller print gamut as best as possible. (but out of gamut is still out of gamut)

The difference s between Relative And Perceptual are often subtle. If you are seeing big jumps between Rel and Per, it may be that your monitor is not profiled/calibrated properly, and those subtle changes are being grossly exagerrated by an improper monitor profile. I was consulting with a client new to color mamagement last week. I was troubleshooting some color problems, and while they demonstrated their workflow to me, they showed me these huge differences while softproofing between Rel and Per. I then discovered they had AdobeRGB selected as their monitor profile, hence the exaggerated differences.
« Last Edit: September 02, 2007, 10:47:30 am by jjlphoto »
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CynthiaM

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Softproofing and rendering intent
« Reply #3 on: September 02, 2007, 11:20:52 am »

Quote
The differences between Relative And Perceptual are often subtle. If you are seeing big jumps between Rel and Per, it may be that your monitor is not profiled/calibrated properly, and those subtle changes are being grossly exagerrated by an improper monitor profile.
[a href=\"index.php?act=findpost&pid=136880\"][{POST_SNAPBACK}][/a]

For the most part, I have seen the subtle differences to which you refer regarding relative and perceptual rendering intent.  When it is more than subtle, I tend to attribute that to a not so great canned printer profile.

But re-read my post; I think you are missing my question.  For this particular image, I am seeing a minimal difference between the soft proof version and non softproof if I try the absolute rendering intent which means I would have less work to do if I choose that rendering intent in terms of further editing to get the soft proof to look more like the original; I wouldn't need to do anything.  I don't know if it is the nature of the image, very high key with little shadow detail, but if I choose relative or perceptual, I would have to play with the image to get the soft proof to look more like the original.  So my question is, in this instance, should I choose absolute since it is closest to the original.  Or am I missing something?

And yes, my monitor is calibrated.

Thanks for your help.
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digitaldog

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Softproofing and rendering intent
« Reply #4 on: September 02, 2007, 11:55:59 am »

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For the most part, I have seen the subtle differences to which you refer regarding relative and perceptual rendering intent.  When it is more than subtle, I tend to attribute that to a not so great canned printer profile.

Don't because that's not the case. ICC profiles don't know squat about images, only the lab values of a pile of solid colors output on the printer. The profile doesn't know that your image is a field of saturated flowers, a black cat on a pile of coal or a white dog kneed deep in snow. The differences can be very subtle, or, with a totally different image, look quite different. This is highly image dependant.
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CynthiaM

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Softproofing and rendering intent
« Reply #5 on: September 02, 2007, 12:35:48 pm »

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This is highly image dependant.
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Andrew:
I appreciate that this is image dependent.  What I am unclear on is whether you should stick with the paper profile (and then choose that paper to print), soft proof, rendering intent that gives the least amount of variation from the original image (when you see the least amount of difference by clicking on/off, ctrl y, command Y on the soft proof).

For example, on some images, if I soft proof using Paper A's profile, there is hardly a difference between the soft proof and the original image.  One would think that if you print using that paper, assuming a color managed system, that your print should look pretty darn close to the non soft proofed image that you see on the monitor.  But with another image, you might see a much bigger jump with Paper A, but not so much with Paper B.

So if my thought process here is on the right track, I'm questioning if I should stick with a particular rendering intent, even if it is one of the less prefered, if it produces a minimal difference between soft proof and original image.
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digitaldog

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Softproofing and rendering intent
« Reply #6 on: September 02, 2007, 12:56:16 pm »

What original? The doc in the working space? Well the differences in rendering intent are based on gamut of course and, its quite possible that you'll see big or small differences from the original (which are only being viewed in an sRGB gamut on most displays) depending on its gamut and that of the profile.

Make a spectral gradient and try the different intents. Paste that into an image, try the two intents. Where do you see the big differences visually? The gradient.
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digitaldog

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Softproofing and rendering intent
« Reply #7 on: September 02, 2007, 01:15:28 pm »

The soft proof and output should match (reasonably close). If not, there's an issue with the profiles (display or if unique to this one paper profile, the two possible tables in the paper profile). If you toggle intents and see something you like, you should get this on output. That one intent in one profile may be preferable tells us something about how the profiles and their rendering is produced. IF you had two paper profiles, both produced output and matching soft proof AND you prefer how one handles the rendering over the other, use the one you prefer. Again, with perceptual rendering, each profile maker will produce a different result. Just like when you set a bunch of cameras to shoot a JPEG, each will produce different color from the same scene. Its not colorimetrically correct. With the Colorimetric tables, yes, they should match (but often don't).
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Bruce Watson

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Softproofing and rendering intent
« Reply #8 on: September 02, 2007, 02:04:14 pm »

Quote
Right now I am working on a file that is very high key, not a lot of color and not a lot of shadow detail.  I've noticed that with this type of image,  if I try the absolute rendering intent that there is a minimal shift between the Photoshop colorspace and the paper profile soft proof color space (when you ctrl, Y or command Y to turn the proof on and off).  Yet I've always read that the perceptual and relative rendering intents are preferable.

So what is advised in this instance?  Stick with the absolute rendering intent and be happy that I don't end up with umpteen soft proof layers and make sure to pick it in the print dialog or stay with perceptual or relative?
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What I advise is learning more about color management, and in particular rendering intents. Just a random pick from the web:

[a href=\"http://www.cambridgeincolour.com/tutorials/color-space-conversion.htm]http://www.cambridgeincolour.com/tutorials...-conversion.htm[/url]

This should give you a better idea of how rendering intents act, and when they act. Basically, it's all about how to handle out-of-gamut pixels. If your image doesn't have any out-of-gamut pixels, then your choice of rendering intent is moot.

ICC Profiles, on the other hand, are largely about insuring that a given color from a given device translates to the same color on a different device. For example, that fire engine red on your monitor translated to a very similar fire engine red on your print.

It seems to me that confusion often comes from the idea that ICC profiles do multiple things. They work to insure color fidelity as above, and they also contain information about the edges of the gamut. Lots of stuff useful in soft proofing and in rendering intents both.
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rdonson

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Softproofing and rendering intent
« Reply #9 on: September 02, 2007, 04:55:32 pm »

Quote
Recently, I started to soft proof when I noticed a loss of shadow detail, particularly on matte papers.  The soft proof adjustments have made all of the difference.  I've noticed when clicking in and out of various paper profiles in the soft proof dialog window, that some profiles make a big jump in brightness/darkness and sometimes in color with hue shift and or saturation.  And then there are some where you barely notice a difference.

Right now I am working on a file that is very high key, not a lot of color and not a lot of shadow detail.  I've noticed that with this type of image,  if I try the absolute rendering intent that there is a minimal shift between the Photoshop colorspace and the paper profile soft proof color space (when you ctrl, Y or command Y to turn the proof on and off).  Yet I've always read that the perceptual and relative rendering intents are preferable.

So what is advised in this instance?  Stick with the absolute rendering intent and be happy that I don't end up with umpteen soft proof layers and make sure to pick it in the print dialog or stay with perceptual or relative?  Link.

Thanks for your thought and comments.
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Cynthia, the most used rendering intents are indeed perceptual and relative colormetic.  Andrew has recommended on numerous occasions though to try the various intents and see which one produces the most pleasing softproof.  You don't mention which Photoshop colorspace you're using though.  ProPhoto RGB, AdobeRGB, etc.?

Generally speaking you'll see the greatest difference in softproofing when using profiles for matte papers.  The reason is the gamut difference between how your original image looks on the monitor and the reduced gamut of matte papers.  Its often startling depending on the image.  There are always adjustments made in softproofing for most papers.

The recently released "From Camera to Print" videos from Michael Reichmann and Jeff Schewe have an excellent section of softproofing.
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jjlphoto

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Softproofing and rendering intent
« Reply #10 on: September 04, 2007, 01:36:33 pm »

The soft proof more closely matches the print when the Simulate buttons are checked. Otherwise, you are stll looking at what is an RGB transmissive image. The Simulate buttom mimics a reflected print.
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CynthiaM

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Softproofing and rendering intent
« Reply #11 on: September 04, 2007, 09:47:18 pm »

Thank you all for taking the time to respond.  The prints came out gorgeous.  Someone had asked what colorspace I'm using.  Mostly Prophoto; sometimes Adobe rgb.  

Will have to download Jeff Schewe's printing video.  Have heard nothing but superlatives about it.
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rdonson

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Softproofing and rendering intent
« Reply #12 on: September 05, 2007, 09:38:33 am »

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Will have to download Jeff Schewe's printing video.  Have heard nothing but superlatives about it.
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I'll second that.  Jeff and Michael did an outstanding job of covering a lot of territory and I think the timing was perfect.
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Eric Myrvaagnes

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Softproofing and rendering intent
« Reply #13 on: September 05, 2007, 10:04:54 am »

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I'll second that.  Jeff and Michael did an outstanding job of covering a lot of territory and I think the timing was perfect.
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And I'll "third" that. I have been making my way through the tutorial very slowly (just over half way now) because there is so much quality info and explanation in every segment.

Jeff and Michael are great team-teachers!
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genemcc

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Softproofing and rendering intent
« Reply #14 on: September 07, 2007, 12:36:07 pm »

Here's another vote for Jeff and Michael's excellent video.  I've just finished it and already am making better prints than ever before!

I'm about to swing through it again because there is just so much great information and I know I didn't absorb it all the first time through.  They make some really esoteric concepts FINALLY understandable!  Kudos gentlemen!!
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