How to get primary (C,M,Y) emulsion paint, e.g. Dulux?

[Chris Nellist]

Hi,

I would like to get some pots of ordinary emulsion paint in the primary colours, i.e. cyan, magenta, and yellow, as used by printers and as easily specifiable in RGB for computer monitors.

The thing is, I need the colours to a high degree of accuracy.

I understand that conversion between the Dulux/ICI codes (or the NCS ones from which they are scrambled) and RGB/CMY codes is not publicly available, so what I will do is get a printer to print out primary C, M, and Y and then take them along to somewhere like B&Q to be scanned with a colour meter. However, I suspect that there may be a big gap between the required colours and the best available matches, since Dulux/ICI probably don't want to encourage people to mix paint.

Any advice would be welcome. Simple question really - how to get pots of primary-colour emulsion paint! :)

Many thanks.

Cheers,

Chris

[Malc]

Johnson and Manders outlets mix paints to any colour you like and will do them to BS numbers as well. So if you can find the number of magenta etc you could be in luck.

I can't see a specific match here but you may be in luck

bit of advice on matching here range of BS numbers that mean nothing to me here

[John Rumm]

Or secondary colurs even ;-)

Not sure if it helps, but Johnstones paint shops will mix Leyland colours to any spec you want.

[stuart noble]

I don't think it's as simple as that with paint because the colours don't exist in pigment form. IIRC geranium red, sky blue, and buttercup yellow are the perfect primaries. Emulsions are all pastel shades anyway so, for a start, you can't get black.

[Chris Nellist]

"stuart noble" IIRC geranium red, sky blue, and

Depends on what you need. Physiologically a green hue would also be included. I want to use the hues defined in HTML as 0/255/255, 255/0/255, and 255/255/0.

I am quite surprised that there aren't more people who buy pots of these three colours and try their hand at mixing up what they want :)

Don't know where you get this idea from. Dulux sell emulsions in dark shades and indeed in black. I don't know how 'pure' a black it is.

Chris

[John Rumm]

I think "mixing" as in with paint, is a different kettle of fish to CMYK printing where you are not mixing but relying on the eye to integrate colours in close proximity to perform subtractive colour mixing.

(You only need look at the huge number of pigment tubes that are present on a paint mixing machine to realise that it's not as simple as printing!)

[Stefek Zaba]

Umm, there's a bit more to colour perception than you seem to acknowledge, Chris. For a start, the HTML "specs" you mention aren't in any "standardised" colour space - they'll give whatever the display device - typcially a CRT or LCD screen - happens to give when driven with (f'r example) "full" Red & Green for the 255/255/0 case, which will be something pretty yellowish; but will appear quite differently on different screens - and different again when printed on a colour printer.

Secondly, for paint mixing you're doing "subtractive" mixing, rather than the additive, and the way particular pigments interact when subtracring depends (and I'm no colour chemist, not even an armature ;-) on a lot more than the absorbtion spectrum of "the" pigment (scare quotes because there's typically more than one pigment involved anyway)

- I'd expect that the grainsize of the pigment, for example, would make quite a difference in how it interacted with other pigments.

Pragmatically, I'd expect you'd get best results for a given colour which the existing "mix-when-you-buy" either don't give you or you feel are overpriced by buying something close, and small pots of the colours you believe necessary to pull the overall colour in the direction you want - from the same mfr, natch, to try to get maximum compatibility in the other components of the paint. But far be it from me to discourage experimentation!

Stefek

[Gernot Hoffmann]

Chris,

offset inks are transparent and normally used on white paper. Samples are in Pantone swatch books, either Pantone Solid or Pantone Process. No need to print samples by a printer. The Lab values for any Pantone Solid or Process ink can be found by Photoshop or by measuring directly in a swatch book by an instrument. The Lab values are not shown in the swatch books. European inks are not exactly the same as US inks. Reference viewing light is D50. No problem to find the few Lab numbers, but the model has to be defined (Pantone Solid, Pantone EuroScale Coated, for example).

Paints (varnishes) are opaque, not defined by Lab and viewing light may be D65 (here I´m not sure about). I didn´t find any cross-reference, but I would recommend to have a look at the RAL system (Google: RAL Colors): e.g.

Some thousands of RAL mixtures are already defined and available in swatch books. Perhaps it is sufficient to choose the nearest RAL color by swatch book comparison.

Just for fun I´ve tried to find a company which mixes paints as specified by Lab - no success so far.

Best regards --Gernot Hoffmann

[Rick Dipper]

We mix our own colours, and have had a few learnings on the way. From experience

- Its not nessecarry to use the same brand, unless its some form of plastic emulsion

- start with a color thats neer what you want

- buy piles of the matchpots from B&Q when they are going cheep

- buy any cheep colors from B&Q when they are end of line

Mix all you need in one go !!!!!

Have Fun

Rick

[Jo Taylor]

You are correct in saying but not for the right reasons.

a. Cyan, Magenta and Yellow are not paint primary colours but transparent printers' ink primaries and rely on overlay not pre-mixing for the effect. Paint primaries are red, blue and yellow and, in emulsion paint, are opaque.

b. The colours Chris wants are available from artists' suppliers in acrylic emulsion.

c. Geranium red, sky blue, etc. are manufacturers' names for certain colours and are not consistent.

d. All colours are available in emulsion, as is black.

Chris, if you could let me know what you want to do with these colours I can probably advise.

Alan Taylor

"stuart noble" exist in pigment form. IIRC geranium red, sky blue, and buttercup yellow are

[Mark Jackson]

Alan Taylor made this same argument nearly a month ago here. Eventually he made some example images available on the Web; unfortunately viewing them required one to be a member of the Yahoo BritArt group. I have rehosted them with his commentary; see

He's got some further words that should accompany the images, but I don't have access to my alumni account from work so will leave it to him to make any additional points here.

[Dave]

but

transparent

Sorry to ask this at this point, but does it make any difference as to which colour is put down first?

Can this be explained to me? I must add that I am some what colour blind here. I was diagnosed as red green colour blind as a child and it has haunted me since. And here is me, interested in photography :-) I get along though ;-) My wife tells me what I have done wrong in PhotoShop, but I wish I did not have to depend on her.

:-(((((

Dave

[Rod Hewitt]

"Dave" wrote in news:cm930i$oph$ [e-mail]:

Yes. For a simple three-colour run, yellow is often the topmost ink as it has the least capacity for hiding the lower inks. Printers have different views of the optimum order. But with a large modern press, there might be ten or more actual printing stations each laying down a different ink. (Not all inks will necessarily be used for all jobs.) Changing the order from run to run is not feasible. So there is probably some order that is regarded as standard for a particular printing process/set of inks/press.

When making colour plates, the dot pattern is produced at different angles for each ink (up to a point, difficult with large numbers of inks) so that there is less chance of a later ink completely obliterating an earlier one. The differing angles basically ensure that the dots in one layer cannot perfectly align with the dots in another layer. This lessens the criticality of the printing order.

My partner's son is also red-green, umm, confused. Hence we have looked around to try to understand the issues. If you have never seen it, is quite amazing. Also,

[Mark Jackson]

This is true of xerographic toners as well.

Actually, I believe this has nothing to do with layered combinations depending on printing order - after all, shifts in relative dot position can't reverse the order, only move from dot-on-dot to dot-off-dot. And *that's* the key - the color you get in these two cases (even for standard, transmissive inks) will be different, certainly because of overlap in the absorption spectra and possibly because of physical effects changing the uptake of the second color.

[The Natural Philosopher]

I am prety sure when I had some paints mixed that teh final color was expressed not only as a mixture of various pigments in a base, but also with CMYK type values as well.

[stuart noble]

No, the actual colours of geraniums, the sky, and buttercups are reckoned to be the perfect paint primaries, but there are no corresponding pigments in the real world.

Compare it to an oil base black and you will see that it is, at best, grey. Practically all blacks tend towards blue, which is why ICI used to charge the earth for a perfect black dye. If the perfect primaries existed, you could mix them in equal parts and get black

[Jo Taylor]

No, brown, if you are talking about paint. Any pair of complementary colours in paint produce a brown with a particular bias depending upon the primary employed. Black is not a colour but an extreme of tone.

[Danny Rich]

Mark,

This is great - our artist friend's Red, Blue Yellow primaries are Quinacridone - a blue-shade red (also known as quinacridone magenta), Pthalocyanine Blue - the standard SWOP cyan, and azo Yellow (the SWOP yellow). So, in fact, his standard RBY primaries are in reality CMY.

End of discussion.

[Danny Rich]

No brown? What happened to Sienna or Burnt Umber? Those used to be in every paint palette set in the art stores that I visited and they are definitely brown.

Danny

[Jo Taylor]

Not quite. These are the names given to a particular range of paints by a particular manufacturer. I have the same colours by other manufacturers and they carry different names and different ingredients. Furthermore, the range in question is from the lower end of the students' quality range which, by definition, contain the minimum of pigment and the maximum of body. If you read the text alongside the samples you will see the colours were chosen solely on the fact the word 'Primary' occured on the tube. The next task is to create a similar test using top of the range artists' colours and make a comparison.

More importantly, transparent printers' inks are pale colours, each with a covering capacity (opacity) of approximately 33%. They are dependant on the reflected white light from the paper for their success. Magenta and Yellow (strictly pale yellow) printers' inks, overlaid on white paper will produce a very good red. Magenta and Yellow paint, mixed on a palette, will produce a pale orange. Cyan and (pale) yellow transparent ink will produce a good green (33% opacity on 33% opacity = 66% opacity). The same colours in paint will produce a pale green. A magenta/cyan ink overlay creates a strong blue whereas a similar paint mix produces a pale purple. The three colours that cannot be made by mixing any paint are red, blue and yellow - the defining factor in establishing the primaries within the RBY system.