Deep blue/cyan

[BobDavid]

I've been taking a lot of photos with dark blue night skies. I am not have much success with being able to get those deep dark blues to print. I am printing with an Epson 7890. I use Epson Premium Luster Photo Paper and Hahnamuhle Photo Rag Baryta paper. The colors are in gamut. The soft proofs on the wide gamut Eizo monitor match perfectly with the prints in the light booth--all except the blues. The monitor is calibrated and I am using Photoshop CC2017 for printing. I have experimented with different rendering intents.

I know from experience that dark blues/cyans are difficult to reproduce on a web press (SWOP).

I am wondering if a RIP will improve RGB to CMYK conversions (RGB files to CMYK output). Any thoughts??

[Eric Myrvaagnes]

Your blues look fine to me.
But since I'm color blind (rather, color deficient), I'm not the best judge.
But blue and yellow are colors that I do pretty well on. It's the reds and greens that are hard for my eyes ("Green" traffic lights look sort of off-white to my eyes.)

[John Nollendorfs]

Bob:
Sometimes you have to play with Hue/Saturation in Blue or Cyan to get it to print the way you want. Just my experience!!!

J.

[BobDavid]

Bob:
Sometimes you have to play with Hue/Saturation in Blue or Cyan to get it to print the way you want. Just my experience!!!

J.

Thanks, but I've done exhaustive experimentation with that as well as bouncing from one color profile to another (CYMK, LAB).

[bill t.]

FWIW here are some Colorthink views of your first "ABC" image as a dot plot on Lab, compared to both my LCD2690 monitor, and then against my iPF8400 profile for Museo Silver Rag.  Silver Rag is not a baryta, but it does have a pretty huge gamut and is much better than average in the blues.

I'll let other more qualified persons make what they will of this.  I will only comment that those very dark blues are either at the very edges of the monitor/paper gamut envelopes, or somewhat outside for the very darkest almost black blues.  Plus we are missing the brightest blues, which is true for just about any media or monitor.  So we've bot a kind of borderline situation on the blues.

I believe you can also view profiles this way on iccview.de.

[Doug Gray]

I've been taking a lot of photos with dark blue night skies. I am not have much success with being able to get those deep dark blues to print. I am printing with an Epson 7890. I use Epson Premium Luster Photo Paper and Hahnamuhle Photo Rag Baryta paper. The colors are in gamut. The soft proofs on the wide gamut Eizo monitor match perfectly with the prints in the light booth--all except the blues. The monitor is calibrated and I am using Photoshop CC2017 for printing. I have experimented with different rendering intents.

The dark blue colors (around Lab (5,5,-22) are not in gamut in Rel. Col or Abs Col. though they are close enough not to trigger the OOG Photoshop mask. However, you are most likely seeing the effect of Epson's flawed profile design.

Specifically, Most Epson canned profiles implement BPC inside the profile and, worse-unlike Canon's also flawed profiles-, report via the AtoB profile tables the wrong colors at very low luminance. It is the reporting back of wrong info (that is the colors reported to be printed are not the ones actually printed)  at low luminance that causes the soft proof to fail in that region.

I know from experience that dark blues/cyans are difficult to reproduce on a web press (SWOP).

I am wondering if a RIP will improve RGB to CMYK conversions (RGB files to CMYK output). Any thoughts??

A custom profile will produce a much better match in these dark blues though it won't change the darkest printable blue. However, the canned Epson profiles, because they implement BPC inside the profile, will print these blues slightly lighter than the printer is capable of and can do if you print using a proper custom profile and Rel. Col. w/o BPC.  This is one of those unusual cases where BPC is best avoided with luster media when the darkest colors are close to the paper's limit.

[BobDavid]

FWIW here are some Colorthink views of your first "ABC" image as a dot plot on Lab, compared to both my LCD2690 monitor, and then against my iPF8400 profile for Museo Silver Rag.  Silver Rag is not a baryta, but it does have a pretty huge gamut and is much better than average in the blues.

I'll let other more qualified persons make what they will of this.  I will only comment that those very dark blues are either at the very edges of the monitor/paper gamut envelopes, or somewhat outside for the very darkest almost black blues.  Plus we are missing the brightest blues, which is true for just about any media or monitor.  So we've bot a kind of borderline situation on the blues.

I believe you can also view profiles this way on iccview.de.

I have a roll of Silver Rag somewhere, I'll give it a try. I wouldn't take a measurement from the little jpeg seriously. It's been compressed and optimized for web viewing, 8-bit sRGB. Some browsers support color profiles, some don't. On the full rez TIFF file, the blues are well within aRGB. I like your idea of trying the Museo paper. ... I wonder if the latest greatest Epson pigment printers are better at handling deep dark blues.

[Doyle Yoder]

I've been taking a lot of photos with dark blue night skies. I am not have much success with being able to get those deep dark blues to print. I am printing with an Epson 7890. I use Epson Premium Luster Photo Paper and Hahnamuhle Photo Rag Baryta paper. The colors are in gamut. The soft proofs on the wide gamut Eizo monitor match perfectly with the prints in the light booth--all except the blues. The monitor is calibrated and I am using Photoshop CC2017 for printing. I have experimented with different rendering intents.

I know from experience that dark blues/cyans are difficult to reproduce on a web press (SWOP).

I am wondering if a RIP will improve RGB to CMYK conversions (RGB files to CMYK output). Any thoughts??

Your statement is confusing. What is you final output device and media.

If your printing to an Epson 7890 why are you consider web press (Swop)? An Epson 7890 can be address as a RGB device so there is no need to consider an RGB to CMYK conversion.

If wanting to simulate an web press (SWOP) then forget the deep blues it ain't possible.

If you print to an web press see if you can profile the web press and convert to that. Still be pretty low gamut but probably be better than (SWOP).

[BobDavid]

Your statement is confusing. What is you final output device and media.

If your printing to an Epson 7890 why are you consider web press (Swop)? An Epson 7890 can be address as a RGB device so there is no need to consider an RGB to CMYK conversion.

If wanting to simulate an web press (SWOP) then forget the deep blues it ain't possible.

If you print to an web press see if you can profile the web press and convert to that. Still be pretty low gamut but probably be better than (SWOP).

I am a huge fan of Dan Margulis. Sometimes, especially with a tricky file, I'll utilize ten channels for achieving optimal results: R, G, B, C, M ,Y, K, L*, a*, b*  This concept worked well back when I ran a fine art reproduction studio. I do not  use SWOP for output, only the profile for adjusting a C,Y,M channel. This technique takes practice. And the big caveat is to beware of destroying data. An Epson 7890 is capable of printing a broader gamut than aRGB. I often process the same RAW file several ways for different attributes. I then layer the TIFFs, and use masking and blending techniques to arrive at the final version. With years of PS experience, the process goes quickly. I think Minor White and Ansel were on point about previsualization. Or in other words, I like to know where I'm going in order to get there. I am trained to "see" the photo prior to clicking the shutter. There are reasons why dark blues/cyans are challenging to reproduce. A lot has to do with the amount of ink required to "build" those colors. Dye process are more adept at handling this problem than pigmented inks.

[Doyle Yoder]

I am a huge fan of Dan Margulis. Sometimes, especially with a tricky file, I'll utilize ten channels for achieving optimal results: R, G, B, C, M ,Y, K, L*, a*, b*  This concept worked well back when I ran a fine art reproduction studio. I do not  use SWOP for output, only the profile for adjusting a C,Y,M channel. This technique takes practice. And the big caveat is to beware of destroying data. An Epson 7890 is capable of printing a broader gamut than aRGB. I often process the same RAW file several ways for different attributes. I then layer the TIFFs, and use masking and blending techniques to arrive at the final version. With years of PS experience, the process goes quickly. I think Minor White and Ansel were on point about previsualization. Or in other words, I like to know where I'm going in order to get there. I am trained to "see" the photo prior to clicking the shutter. There are reasons why dark blues/cyans are challenging to reproduce. A lot has to do with the amount of ink required to "build" those colors. Dye process are more adept at handling this problem than pigmented inks.

Why would you not use a Wide Gamut CMYK profile to do this?

[BobDavid]

Why would you not use a Wide Gamut CMYK profile to do this?

Either I am not communicating clearly or you are missing the point. No, one doesn't require a wide gamut monitor for CMYK. Yes, a wide gamut monitor is appropriate for aRGB.

There are situations where it's impossible to isolate a channel in a given color space. I suggest you read Dan's book: Photoshop LAB Color: The Canyon Conundrum and Other Adventures in the Most Powerful Colorspace.

[Doyle Yoder]

Either I am not communicating clearly or you are missing the point. No, one doesn't require a wide gamut monitor for CMYK. Yes, a wide gamut monitor is appropriate for aRGB.

There are situations where it's impossible to isolate a channel in a given color space. I suggest you read Dan's book: Photoshop LAB Color: The Canyon Conundrum and Other Adventures in the Most Powerful Colorspace.

I must be missing the point.

I just thought the problem was that you were not achieving (printing) the deep blues you wanted when you were converting to a limited color space and then wondering why.

I probably should read Dan's books but I recall reading a lot of Dan's writings and as I recall most of what he was talking about was outputting to conventional offset presses.

I understand why you might want to use CMYK but why convert the RGB to a very gamut limiting SWOP profile when you could be converting to a wide gamut CMYK profile instead.

[BobDavid]

I have not been able to find a wide gamut cmyk profile that is compatible with Epson UltraChrome K3 ink. Am I missing something here?

[Czornyj]

What you're missing is that it's RGB device. There's no reason to use any CMYK space just to convert it to RGB at the end of the day. Use broader RGB and you'll acheive the very same effect with less rounding errors. Margulis is soooo 90s...

[BobDavid]

What I've gleaned from this thread is that current pigment ink sets and papers are are the limiting factors in improving upon deep blue/cyan reproduction.

I appreciate your suggestions and feedback. For now, I am satisfied to put the issue to rest.