Mike Chaney's Tech Corner

Mike's Software => Qimage Studio Edition => Topic started by: mical on March 12, 2010, 10:59:12 AM



Title: Perceptual or Relative colourmetric ?
Post by: mical on March 12, 2010, 10:59:12 AM
Scanning very old b/w negs to RGB files for restoration and to add limited colours in PS(see attachment). When printed on  gloss paper, (Ilford smooth high gloss), all is good - i.e. neutral grays and accurate colour and very little metamerism.
However, printing on matte paper, metamerism is an issue when viewed under artificial lighting.
Question: any recommendations for a matte paper that is not prone to metamerism for this type of print output and regarding rendering intent would relative colourmetric be best?
My printer is on old Epson 2100. I am using pigment CIS system Photo black. All my profiles are created using PP and printed through QSE.
Many thanks
Alan
(added a copyright to pic)


Title: Re: Perceptual or Relative colourmetric ?
Post by: Jeff on March 12, 2010, 11:36:16 AM
Where was that photo taken? looks like a 1947 ish at Torquay, I am sure I can remember subs being there about then.

Jeff



Title: Re: Perceptual or Relative colourmetric ?
Post by: rayw on March 12, 2010, 03:04:04 PM
Hi Alan,

Not quite sure of the cis system you are using, but possibly you are printing on matte paper with photo black ink. You probably need to use a matte black, which may reduce the geometric metameric failure. Also, if you are viewing the print under fluorescent lighting, it will tend to enhance the illuminant metameric failure.

wrt the rendering intent - try it and see is my best advice.

If it is critical to your work, then I would suggest you speak with specialist paper/ink suppliers. I could recommend fotospeed if you are in the UK. They have a good range of papers, and a practical knowledge of their products.  I am sure there are similar suppliers elsewhere.

Best wishes,
Ray


Title: Re: Perceptual or Relative colourmetric ?
Post by: mical on March 16, 2010, 04:54:20 PM
Where was that photo taken? looks like a 1947 ish at Torquay, I am sure I can remember subs being there about then.

Jeff


hi Jeff, my research suggests location is Devonport, Plymouth.  H29 sank there in 1926. The H class were single hull trainer boats designed towards the end of WW1 c1916. This photo was originally taken c1920.
Regards
Alan


Title: Re: Perceptual or Relative colourmetric ?
Post by: mical on March 16, 2010, 05:07:17 PM
Hi Alan,

Not quite sure of the cis system you are using, but possibly you are printing on matte paper with photo black ink. You probably need to use a matte black, which may reduce the geometric metameric failure. Also, if you are viewing the print under fluorescent lighting, it will tend to enhance the illuminant metameric failure.

wrt the rendering intent - try it and see is my best advice.

If it is critical to your work, then I would suggest you speak with specialist paper/ink suppliers. I could recommend fotospeed if you are in the UK. They have a good range of papers, and a practical knowledge of their products.  I am sure there are similar suppliers elsewhere.

Best wishes,
Ray


Hi Ray,Thanks for your imput, I will check out Fotospeed.
Regards
Alan


Title: Re: Perceptual or Relative colourmetric ?
Post by: Seth on March 31, 2010, 11:16:50 AM
I agree.  Sounds like the wrong black ink.  I have never heard of metamerism on matte paper.

The color shift in incandescent light would be normal though.  You have to run your test prints under the same light as the final print will be viewed in.  Silver photographicprints suffered the same issue.


Title: Re: Perceptual or Relative colourmetric ?
Post by: willym on May 01, 2010, 04:05:11 PM
Hi Alan-

What are you using to scan the negs?
Regarding the conversion, for B&W it should make very little difference- the intent (RC or Perc.) determines how the converter handles out of gamut colors, which I doubt you have here. That said, sometimes you'll see a difference, usually the Perc. is somewhat lighter in the mid-tones and highlights.

However, sometimes you'll also see a difference where with perc. you lose some of the darkest shadows- obviously a problem printing on matte papers!
See my new post about weirdness of Photoshop conversions versus converting in Qimage- suffice it to say that Qimage is different, and better. I am still trying to puzzle this one out!

Feel free to call if you want to discuss this further.

Regards,

Bill Morse
William Morse Editions
MorseEditions.com

Scanning very old b/w negs to RGB files for restoration and to add limited colours in PS(see attachment). When printed on  gloss paper, (Ilford smooth high gloss), all is good - i.e. neutral grays and accurate colour and very little metamerism.
However, printing on matte paper, metamerism is an issue when viewed under artificial lighting.
Question: any recommendations for a matte paper that is not prone to metamerism for this type of print output and regarding rendering intent would relative colourmetric be best?
My printer is on old Epson 2100. I am using pigment CIS system Photo black. All my profiles are created using PP and printed through QSE.
Many thanks
Alan



Title: Re: Perceptual or Relative colourmetric ?
Post by: mical on July 20, 2010, 08:35:21 AM
Hi Bill, apologies for not replying until now, illness reared its ugly head.
The hardware I use is an Epson Perfection flatbed 3200 scanner,old but ok for me.
The software is Silverfast AI Studio. Using the 'multiscan 2 or 4 passes' does a really good scan.
Thanks for the pointers you raised.
Regards
Alan

Hi Alan-

What are you using to scan the negs?
Regarding the conversion, for B&W it should make very little difference- the intent (RC or Perc.) determines how the converter handles out of gamut colors, which I doubt you have here. That said, sometimes you'll see a difference, usually the Perc. is somewhat lighter in the mid-tones and highlights.

However, sometimes you'll also see a difference where with perc. you lose some of the darkest shadows- obviously a problem printing on matte papers!
See my new post about weirdness of Photoshop conversions versus converting in Qimage- suffice it to say that Qimage is different, and better. I am still trying to puzzle this one out!

Feel free to call if you want to discuss this further.

Regards,

Bill Morse
William Morse Editions
MorseEditions.com

Scanning very old b/w negs to RGB files for restoration and to add limited colours in PS(see attachment). When printed on  gloss paper, (Ilford smooth high gloss), all is good - i.e. neutral grays and accurate colour and very little metamerism.
However, printing on matte paper, metamerism is an issue when viewed under artificial lighting.
Question: any recommendations for a matte paper that is not prone to metamerism for this type of print output and regarding rendering intent would relative colourmetric be best?
My printer is on old Epson 2100. I am using pigment CIS system Photo black. All my profiles are created using PP and printed through QSE.
Many thanks
Alan

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