Non-photo blue
en.wikipedia.org
Non-photo blue
1–10 of 44 posts
Re: Non-photo blue
#2When the article refers to 'graphics-arts cameras', what do they mean?
Is there a spectral notch filter applied to the CCD, or is the article a troll?
"Scanning in black-and-white makes it possible for the non-photo blue still to serve its original purpose, as notes and rough sketching lines can be placed throughout the image being scanned and remain undetected by the scan head."
Any black-and-white scanner should have a spectrally-flat response, picking up blue just as black and white photographs see the sky as darker than white.
It's entirely possible that older lithographic film didn't have much response in the blue, but there's really no way that a modern imaging system won't pick it up.
What am I missing?
Edit: Experiment is the arbiter of truth: I took a picture of the screen with my digital SLR. As expected, every color swatch in the article is blue. Desaturated the RAW image. Looks grey.
Re: Non-photo blue
#3Somewhat related:
https://en.wikipedia.org/wiki/International_Klein_Blue
Also I fondly remember Hubertus Bigend's IKB suit…
Re: Non-photo blue
#4When the article refers to 'graphics-arts cameras', what do they mean? Is there a spectral notch filter applied to the CCD, or is the article a troll? "Scanning in black-and-white makes it possible for the non-photo blue still to serve its original purpose, as notes and rough sketching lines can be placed throughout the image being scanned and remain undetected by the scan head." Any black-and-white scanner should ha…
[deleted]
Re: Non-photo blue
#5When the article refers to 'graphics-arts cameras', what do they mean? Is there a spectral notch filter applied to the CCD, or is the article a troll? "Scanning in black-and-white makes it possible for the non-photo blue still to serve its original purpose, as notes and rough sketching lines can be placed throughout the image being scanned and remain undetected by the scan head." Any black-and-white scanner should ha…
I believe they are referring to a technology of the ancients where they made thin films of photosensitive chemicals, exposed them to light, then processed them to make images. The chemicals varied in which wavelengths would activate them.
For instance, red would not activate the paper commonly used for black and white prints, hence the red lights in dark rooms.
It is also possible the cameras illuminated the artwork with a light to which the non photo blue ink was transparent.
Re: Non-photo blue
#6When the article refers to 'graphics-arts cameras', what do they mean? Is there a spectral notch filter applied to the CCD, or is the article a troll? "Scanning in black-and-white makes it possible for the non-photo blue still to serve its original purpose, as notes and rough sketching lines can be placed throughout the image being scanned and remain undetected by the scan head." Any black-and-white scanner should ha…
It's a real thing: in ancient times when I worked on a yearbook staff, we used non-photo blue markers to mark up the physical pages we sent to the publisher.
I don't know how these pre-digital reproduction systems excluded the blue, nor to I know if this system is still in use in the digital era.
Re: Non-photo blue
#7When the article refers to 'graphics-arts cameras', what do they mean? Is there a spectral notch filter applied to the CCD, or is the article a troll? "Scanning in black-and-white makes it possible for the non-photo blue still to serve its original purpose, as notes and rough sketching lines can be placed throughout the image being scanned and remain undetected by the scan head." Any black-and-white scanner should ha…
The "graphics arts cameras" they are referring to are pre-digital. They looked like this: http://www.forgottenartsupplies.com/?what=artifacts&image_id...
The goal was to compose a layout into a single image.
You created a layout by literally cutting and pasting things onto a board. Then you placed that board in the area at the bottom and took a picture of it that was transferred to film loaded in the top.
You're right that the film was special; but it's the other way around from how you were thinking. The film was not sensitive to red light. To this film, red is "black" and cyan or blue is "white".
Why this was useful:
- You could open the box of film (it came in sheets) in a room that was darkened except for a red bulb, without exposing it.
- You could use overlays of transparent red material (rubylith) to mask things precisely. Even though you could see through to the layer below, the camera would see it as all black.
- And, as the article mentioned you can add notes to the layout with blue pencil and it would be invisible to the transfer. We always called this "non-repro blue" though, as in, the camera wouldn't reproduce it.
Re: Non-photo blue
#8And my engineering notebooks from the EurekaLabNotebook company use this color for the grid which is a bit disconcerting if you make a copy of the page and the grid disappears and you have only your writing and diagrams.
Re: Non-photo blue
#9When the article refers to 'graphics-arts cameras', what do they mean? Is there a spectral notch filter applied to the CCD, or is the article a troll? "Scanning in black-and-white makes it possible for the non-photo blue still to serve its original purpose, as notes and rough sketching lines can be placed throughout the image being scanned and remain undetected by the scan head." Any black-and-white scanner should ha…
The "graphics arts cameras" they are referring to are pre-digital. They looked like this: http://www.forgottenartsupplies.com/?what=artifacts&image_id... The goal was to compose a layout into a single image. You created a layout by literally cutting and pasting things onto a board. Then you placed that board in the area at the bottom and took a picture of it that was transferred to film loaded in the top. You're righ…
Kind of strange for the info box to specify a color used in the pre-digital era using a digital sRGB triplet.
Re: Non-photo blue
#10When the article refers to 'graphics-arts cameras', what do they mean? Is there a spectral notch filter applied to the CCD, or is the article a troll? "Scanning in black-and-white makes it possible for the non-photo blue still to serve its original purpose, as notes and rough sketching lines can be placed throughout the image being scanned and remain undetected by the scan head." Any black-and-white scanner should ha…
It's a real thing: in ancient times when I worked on a yearbook staff, we used non-photo blue markers to mark up the physical pages we sent to the publisher. I don't know how these pre-digital reproduction systems excluded the blue, nor to I know if this system is still in use in the digital era.
[deleted]