tag:blogger.com,1999:blog-1840985738235902482.post3344070108450551387..comments2024-03-27T07:14:48.488-04:00Comments on John the Math Guy: How many colors are in your rainbow?John Seymourhttp://www.blogger.com/profile/11350487038873935295noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-1840985738235902482.post-28534071560399279662014-03-23T18:01:30.271-04:002014-03-23T18:01:30.271-04:00You may recall prior to softproofing, drum scanner...You may recall prior to softproofing, drum scanner operators could only trust the screen tint Atlas books. These were printed with the printers own press, paper and inks. The step increment bewteen blocks or patches was 5%. So, from 0-100% there wer 20 steps for each color. 20C x 20M x 20Y = 8,000 colors. Adding K for another x20 (160,000) was redundant and not needed.<br /><br />Steve Suffoletto SSuffoletto@BuffNews.comAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-13163578665796312392013-01-21T14:46:26.084-05:002013-01-21T14:46:26.084-05:00Thanks, Jeff, for seeing a very practical consider...Thanks, Jeff, for seeing a very practical consideration of this somewhat fanciful discussion.<br /><br />Are 8 bits enough? It would seem that maybe they are, except that they might not be distributed appropriately. The eye is nonlinear. At the high end (near 255) we might not notice a change of even a few gray levels. At the dark end, our eye is more sensitive, and one gray level might be huge.<br /><br />But, on the other hand, cameras are historically not linear beasts. They have a gamma associated with them, which boosts the midrange. Industrial cameras used to have an analog circuit to do this gamma. Today they generally have 10 bits or so feeding into a look up table to make this gamma. There is usually a switch to turn this off.<br /><br />As a result, there is compression in camera images at the high end, and stretching at the low end. This means that the camera sees something more similar to what our eye sees, so 8 bits isn't so bad.<br /><br />But on the third hand, images don't all come from cameras, and are often displayed on a monitor. The whole gamma thing came up back when we were using CRT displays, which are very nonlinear. We needed to boost the midrange to make images look correct. Rather than fix the monitor (maybe by adding a profile) camera manufacturers jumped on a solution.<br /><br />Today, monitors are closer to linear, so... I dunno what this means! I'm confused. Is there a lookup/profile between the monitor I am looking at right now, and the image that is displayed via Windows? <br /><br />I guess... if an image has a gamma associated with it and it is understood that the gamma has been applied, and what the gamma is, then 8 bits might be just enough.John Seymourhttps://www.blogger.com/profile/11350487038873935295noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-20428864417202862702013-01-21T14:25:52.240-05:002013-01-21T14:25:52.240-05:00Great article John. I thought the CIELAB point was...Great article John. I thought the CIELAB point was especially interesting. If there are roughly 2 million "just noticeable" steps in CIELAB would that mean that the current standard bit depth of 8-bits/channel is sufficient for even the largest color gamuts? I've heard a lot of concern about banding with 8-bits and wide gamut but it strikes me that 16+ million colors might be enough headroom except in the most extreme, not found in nature, cases.Anonymoushttps://www.blogger.com/profile/00743995315908551370noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-85944297639899489752012-10-03T05:56:54.564-04:002012-10-03T05:56:54.564-04:00John, what I forgot to say was thank you for a fan...John, what I forgot to say was thank you for a fantastic articleAnonymoushttps://www.blogger.com/profile/12812446759357104801noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-61869196674802324562012-09-25T23:44:44.843-04:002012-09-25T23:44:44.843-04:00Great musical, Steve! That totally slipped my min...Great musical, Steve! That totally slipped my mind. :)John Seymourhttps://www.blogger.com/profile/11350487038873935295noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-41761342714668419952012-09-25T18:47:44.630-04:002012-09-25T18:47:44.630-04:00we need look no further than Joseph and the amazin...we need look no further than Joseph and the amazing technicolor dreamcoat.<br />the answer is clearly 29 (or maybe 27, or 26 if you're an art teacher).<br />red and yellow and green and brown and<br /> Scarlet and black and ochre and peach<br /> And ruby and olive and violet and fawn<br /> And lilac and gold and chocolate and mauve<br /> And cream and crimson and silver and rose<br /> And azure and lemon and russet and grey<br /> And purple and white and pink and orange<br /> And blue<br />Newton, phah...Tim Rice and Andrew Lloyd Webber have the answers (except for silver and gold.....oh yeah, and black)Anonymoushttps://www.blogger.com/profile/12812446759357104801noreply@blogger.com