Colour matching.

[Robin GrahamParticipant @robingraham42208]

I make things mostly for my own use, but occasionally take on 'beer token' jobs for others when I think I can learn something. The latest is a simple enough engineering project, but needs to be colour matched. I've never tried that (my stuff is either shiny or black) – so I'm wondering how people go about it.

All I have is a photograph, which isn't much to go on I know. But GIMP will give me RGB values. Would that be that enough to identify a RAL colour?

I suspect that I'm dipping my toe into deep water here, and might not want go further, but I'd be interested in any advice.

Robin.

Edited By Robin Graham on 01/01/2020 23:51:37

[Robin GrahamParticipant @robingraham42208]

[Frances IoMParticipant @francesiom58905]

unlikely unless you are already into photogramy + have calibrated your camera + monitor
You can buy small sheets showing a range of standard colours (I’ve seen them around (possibly free) at UK National Archives at Kew but not my interest) – photographing the object + including one of these small sheets will probably give you a good indication tho even here different lighting may well affect your camera response

[Michael GilliganParticipant @michaelgilligan61133]

Try this, Robin …

• Go to EasyRGB and input those RGB values [or the Hex] & select RAL from the drop-down list of 'color collections' … It will then display your input colour and the four nearest RAL colours. Any decent paint-shop can work from RAL, or you can choose a different 'collection' if you prefer.

MichaelG.

[JasonBModerator @jasonb]

Go to a paint shop and get them to scan it., Assume you will need to buy the paint anyway rather than mix your own.

Or if you can say what the item is the colours may be listed somewhere like they are of old machine tools, engines etc. Though that won't take into acount any fading or staining.

[David JuppParticipant @davidjupp51506]

Be aware that the type of light source used to illuminate will affect the perceived/measured colour.

Matching the colour under one light type, won't always give a match under other lights.

Good luck.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Robin Graham on 01/01/2020 23:43:25:

[…]

All I have is a photograph […]

.

[duncan webster 1Participant @duncanwebster1]

Take your photo to the man who mixes car paint, he will be able to scan it on his machine and mix up some paint. There are at least 2 in my local town, so you shouldn't struggle to find one

[Nick WheelerParticipant @nickwheeler]

You need to match to the actual paint, a photo won't do. Anyone who mixes custom paint should do that, but they'll need to see a sample to do it. Can your customer remove a small painted piece and organise that local to him? You will need to tell him what type of paint you want – the paints used on cars will be easy to sort, but other types might be a lot more difficult.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Nicholas Wheeler 1 on 02/01/2020 11:25:59:

You need to match to the actual paint, a photo won't do. […]

.

Which is exactly why I suggested that Robin’s first approach should be to use EasyRGB

… Given that he is considering using GIMP to extract an RGB value, it seems reasonable to assume that he has a digital image rather than a physical print.

That image will almost certainly have numerous colour imperfections, but it’s the closest he has to a sample.

A few minutes exploring EasyRGB will at least give him a colour to discuss with the beer token holder.

MichaelG.

[Robin GrahamParticipant @robingraham42208]

Thanks. I do indeed have only a digital image to work from, and MichaelG's suggestion of EasyRGB seems a good place to start. I can't be blamed if I'm doing the best with the info I've got!

The 'customer' actually said "some degree of colour matching would be required" so maybe it doesn't need to be exact. Anyhow, a learning opportunity for me, I'll follow it up. I suspect that the customer might not understand that for hand made work aesthetic finishing can take longer than making the functional parts.

Robin

[Nick Clarke 3Participant @nickclarke3]

Posted by Robin Graham on 03/01/2020 00:32:03:

The 'customer' actually said "some degree of colour matching would be required" so maybe it doesn't need to be exact.

From some hard experience in matching car paint (part of my job in the seventies before scanners were ever thought of) 'Some degree of colour matching would be required' reads to me as 'This needs to be exact but I can't tell you what colour it is'

I would go back and get it confirmed if I were doing the job.

[JohnFParticipant @johnf59703]

Why not ask your punter to take the original item to his/her local paint shop/supplier and have it scanned then either purchase the paint or send you the RGB colour code ?

John

[CirclipParticipant @circlip]

Long short, Made some between the seat litter bins for BREL, Drawing specified Powder coat Grey to BS whatever (Can't remember spec now). Coating had to be applied by a powder coater as we had no painting facilities. Sent first batch of 12 and following day received a call to urgently go to York works as colour was wrong. Side by side comparison to ours as opposed to a stock item was chalk and cheese, had a colour chip stuffed under my nose to prove this. Went back to give powder coater a stuffing who then proceeded to get the BS colour manual out and their coated bins were exactly the same colour as the manual.

Took a LOT of teeth pulling to get BREL to admit the colour was "Their" BS grey and was in fact NOTHING to do with British Standards but was a laboratory mix by a powder manufacturer of a colour agreed between a BREL designer and the Lab manager. Result being ALL powder coated items of that colour had to have powder supplied by that lab which just happened to be twice the cost of other manufacturers of raw powders.

The above, one of MANY landmines in being given the "Privilege" of supplying BREL as an external supplier.

Safe advice? I'll make it, YOU get it painted. Bitter voice of experience.

Regards Ian.

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