RGB? CMYK? Pantone 92?

Message Bookmarked

Bookmark Removed

I know so little about colour. Tell me a little thing you know.

Another thread I can't categorise.

― N. (nickdastoor), Tuesday, 11 February 2003 12:12 (twenty-three years ago)

The limited selection of non-dithering colors (http://www.lynda.com/hexh.html) explains a lot about web design.

― Douglas (Douglas), Tuesday, 11 February 2003 12:26 (twenty-three years ago)

RGB is what you see on a screen, it is an additive colour model. Add them all together and you get white.
CMY(K) is what you see on a page, it is a subtractive colour model. Add CMY together and you get Black (actually a muddy grey, which is why we use the extra K)
Pantone colours are pure colours that can be mixed from a standard set of inks. Like picking a wallpaper colour. Running a fifth or 'spot' colour is usually done to exactly match a colour that can't be matched from CMYK values.

The full range of colours that can be produced from any given colour model is known as the gamut. Gamut is a great word.

― Simeon (Simeon), Tuesday, 11 February 2003 13:25 (twenty-three years ago)

If you don't need to know, trust me, you don't WANT to know!

But anyway, basically RGB is additive colour, 100%RED+100%GREEN+100%BLUE = WHITE, this system is primarily used in televisions and monitors. You also have the printing system CMYK, which is subtractive colour 100%CYAN+100%MAGENTA+100%YELLOW+100%BLACK = Big horrible dark, wet sheet of paper in danger of ripping. You can create black quite succesfully using just CMY, but K (for keyline or blac'K') is used so you don't get text looking blurry because the different 'plates' are out of register during the printing process.

Pantone is a system to ensure a correct colour match over a variety of different printing processes and/or paper-types. This colour match is either done by using CMYK, or by mixing an exact colour together and having a separate plate just for this 'spot' colour.

See, you didn't want to know.

― Chewshabadoo (Chewshabadoo), Tuesday, 11 February 2003 13:32 (twenty-three years ago)

Damn you!

― Chewshabadoo (Chewshabadoo), Tuesday, 11 February 2003 13:33 (twenty-three years ago)

Haha Chewshabadoo, I am mjust getting started!

The first printed images were 1 colour engravings, these are like 1bit computer files. The ink is there or not, it's black or white with no shades of grey.
Photographic images are reproduced on paper by printing dots of varying sizes to give the illusion of continous tone when viewed from a distance.
When done with 4 or more ink colours you can reproduce the illusion of a photographic image on paper.

― Simeon (Simeon), Tuesday, 11 February 2003 13:35 (twenty-three years ago)

Colours on screen will display differently on Mac and PC computers due to the different graphics hardware (apparently Mac is more 'accurate' - one reason why they are often favoured in design/artworker field)....in turn these will often not quite match what is eventually printed on paper, should you wish to output on paper as well as on screen. The implications of this are not terribly important as the minor differences will usually go unnoticed by the majority of people.

Another tip: when using CMYK colours, always resist using more than two colours i.e. everything should be composed of just two plates e.g. 60% Cyan 40% Yellow 0% Magenta 0% Black - using lots of Cyan, Yellow and Magenta together can often mess things up.

― stevem (blueski), Tuesday, 11 February 2003 13:37 (twenty-three years ago)

On screen things are a bit different.
Imagine a grid where every cell can be either on or off, this is like a 1 bit image.
Now imagine that each value can be 1 of 8 shades of grey, this is a grey scale image.
Now imagine you've got three planes of these, each one either RG or B. 8x8x8 means that each cell could be one of 256 different colours, this is your standard 8-bit VGA image.

Modern fangled computers can store 24-bits (or more) per channel giving you 256x256x256= 16m colours available to you onscreen.

― Simeon (Simeon), Tuesday, 11 February 2003 13:53 (twenty-three years ago)

More!

― N. (nickdastoor), Tuesday, 11 February 2003 13:57 (twenty-three years ago)

colour theory is quite interesting in a Changing Rooms kinda way, colourwheels and how different colours go together well, contrast well, stuff like that. primers all over the web:

http://www.webdesignclinic.com/ezine/v1i1/color/index.html

have also started using hsb (hue, saturation, brightness) colour model when coding recently - makes it very easy to get a nice, random range of complimentary colours for things like screensavers and dhtml recreations of channel 4 interval clips. it's just another way of specifying a colour, just like polar and cartesian co-ords are two different ways of positioning a point in space.

http://www.cecs.csulb.edu/~jewett/colors/hsb.html

andy

― koogs, Tuesday, 11 February 2003 14:03 (twenty-three years ago)

What else do you need to know N?
Did you do the colourblindess test?
Are you Colourblind?

Just search for "colour theory" you idle boy!

― Simeon (Simeon), Tuesday, 11 February 2003 14:13 (twenty-three years ago)

You can calibrate the colour representation of your Mac cusing the colour sync utility. It will allow you to ensure that colours stay accurate right through your workflow. If you want to get really serious you can use a colourimiter to calibrate all of your hardware so what you see on screen, and what you scan in is what comes out of the printer.

― Ed (dali), Tuesday, 11 February 2003 14:50 (twenty-three years ago)

Have you noticed how if you screen dump to Photoshop after doing Alt+print screen, you can't then save the resultant image in a compressed format (e.g. GIF) unless you first use the Flatten Image function, to reduce the 256 million colours to 8 bit colour. This is because a compressed image format holds less info, and thus occupies less disk space, by having fewer colours. Why flatten? well, I suppose you can think of it visually as flattening a range of colours down to a single colour which approximates it.

― MarkH (MarkH), Tuesday, 11 February 2003 15:09 (twenty-three years ago)

You're kinda right MarkH, but not quite. You need to index the colours in an image in order to use the gif format (mode>indexed colour). Indexing scans through the image and chooses the 256 colours that occur most frequently in the image giving the image an 8-bit colour look up table (CLUT) reducing your original 24bit image to a tiny 8bit file.
(Flattening the image just merges all the layers of the doc)

Compression can be lossy or non-lossy. Gif is a lossy format as it throws away colour information to reduce the filesize.
Jpg's are lossy as they use a fractal algorithm to find similar groups of pixels and repeats these groups to reassemble an aproximation of the original image.
Tif's can be losslessly compressed using a flavour of RLE called LZW. This looks at a lines of similar pixels and replaces them with a shorter instruction for reproducing the original structure.
EG 1,1,1,1,1,1,1,1 would become 8-1's

PNG files can do alll of the above, but no one uses this format.

― Simeon (Simeon), Tuesday, 11 February 2003 15:25 (twenty-three years ago)

i'm using PNG more and more for web images, i think it is catching on slowly

― stevem (blueski), Tuesday, 11 February 2003 15:31 (twenty-three years ago)

More, heh, N doesn't even need to know this, he's just enjoying cracking the whip.

― Sean (Sean), Tuesday, 11 February 2003 15:55 (twenty-three years ago)

Long live squant.

― Ned Raggett (Ned), Tuesday, 11 February 2003 16:15 (twenty-three years ago)

GIVE ME MORE COLOUR FACTS!

― N. (nickdastoor), Tuesday, 11 February 2003 16:26 (twenty-three years ago)

I have green eyes.

― Lara (Lara), Tuesday, 11 February 2003 16:30 (twenty-three years ago)

My favourite colour is Blue. ~80% of my wardrobe is a shade of blue.
Bellybutton fluff is always blue (mine is anyway).

― Simeon (Simeon), Tuesday, 11 February 2003 16:51 (twenty-three years ago)

When I was 4 and was about to move "up north", my uncle told me that it was all in black and white and the men had whippets and said "eee bah gum". I cried.
Turns out he was lying about the black and white bit.

― Simeon (Simeon), Tuesday, 11 February 2003 16:53 (twenty-three years ago)

> Gif is a lossy format as it throws away colour information to reduce the filesize.

isn't quite right. gif will hold an image (up to 256 colours) without loss - you threw the colour information away whilst doing the "mode>indexed colour" transformation.

> Indexing scans through the image and chooses the 256 colours that occur most frequently in the image giving the image an 8-bit colour look up table (CLUT) reducing your original 24bit image to a tiny 8bit file.

also not quite right. the 256 colours it chooses don't necessarily have to be in the original image. in photoshop it allows you to pick 'adaptive', 'exact', 'web', 'custom' and a couple of other options. adaptive will pick the best 256 regardless of whether they are currently in the image, 'exact' is used when the original image has less than 256 colours in it, 'web' will pick from a palette of websafe colours, 'custom' lets you choose the palette of colours that it'll remap to. the actual remapping of the colourspace to the new palette is done either by picking the new colour closest to the original colour or some kind of dithering.

um, an example of dithering: you have a greyish image but the new palette only has black and white in it. so the resulting image has that black and white checkerboard effect to it so it looks grey from a distance.

oh, and jpegs don't use a fractal algorithm but a discrete cosine transform to get rid of information that isn't useful...

andy

― koogs, Tuesday, 11 February 2003 16:54 (twenty-three years ago)

I hate the colour blue.

― Lara (Lara), Tuesday, 11 February 2003 16:54 (twenty-three years ago)

gif is great for things that only contain a limited number of colours. I get very annoyed when web developers make two colour buttons and the like JPEGs rather than GIFs especially when the JPEG compression is so high that the colour gets fucked. Web designers really ought to be forced to learn some basic technical skills.

― Ed (dali), Tuesday, 11 February 2003 16:59 (twenty-three years ago)

Web designers really ought to be forced to learn some basic technical skills

HAHAHAHAHAHAHAHAHAHAHAHAHA

― Alan (Alan), Tuesday, 11 February 2003 17:10 (twenty-three years ago)

Koogs is OTM on all points.

Synaesthesia is a condition where sufferers can percieve sounds as colours (and other mixed senses - smelling colours etc) I read about this when I was v.young and always thought it would be cool to try.

Oh and AlanT to thread!

― Simeon (Simeon), Tuesday, 11 February 2003 17:15 (twenty-three years ago)

yes hello, i've not been around much, but i see you have everything in order here.

http://www.prism.to/glossary.htm

― Alan (Alan), Tuesday, 11 February 2003 17:17 (twenty-three years ago)

That bouncing banner should be banned.

― N. (nickdastoor), Tuesday, 11 February 2003 17:18 (twenty-three years ago)

there is a growing trade in "prestige" hexachrome printed wrapping paper. hexachrome printing is very much like CMYK but with added "gamut" (ability to repro a wider range of colours) because it used a 5th and 6th plate that cover the oranges and greens that CMYK can't quite reach. However when using grids of varying size dots (halftoning explained above) then the best you can do is overlay/mix up to 3 colours, though you can get away with 4 if the 4th is weak -- as indeed yellow is. So hexachrome printing can't use this regular "amplitude modulation" method of halftoning -- you'll get horrid moire patterns no matter what "angles" the grids are printed at. instead you have to use a stochastic "frequency modulation" which put simply is spattering lots of tiny spots randomly, much in the way that desktop colour inkjet printers already do. this method won't work with traditonal photographic film-based work though (or so I am told) because the tiny spots don't keep their fidelity well.

http://www.ekdahl.org/kurs/bilder/faq_gamut.jpg

― Alan (Alan), Tuesday, 11 February 2003 17:28 (twenty-three years ago)

Now that last post was actually quite interesting (comparatively.)

― Chewshabadoo (Chewshabadoo), Tuesday, 11 February 2003 20:06 (twenty-three years ago)

agreed!

― stevem (blueski), Tuesday, 11 February 2003 20:14 (twenty-three years ago)

twenty-two years pass...

https://www.youtube.com/watch?v=TvHL0AVHMX4

― Maresn3st, Thursday, 11 December 2025 10:11 (six months ago)

thought this revive would be about their racist colour of the year.

― ledge, Thursday, 11 December 2025 10:26 (six months ago)

Pantone 88

― assert (matttkkkk), Thursday, 11 December 2025 10:46 (six months ago)

You must be logged in to post. Please either login here, or if you are not registered, you may register here.