colour matching paint - why not simple?

[El Donkey]

Now I know colours can change a little over time and they are mixed by weight but....

Why should they not be much closer and blending be less of an issue?

You'd think a paint could be scanned and replicated exactly by now?

 

[daveypower]

i think they can be scanned now, also its how well its applyed, what colour of primer is used, and if the car was ever touched up before, plus as you know with age paint fades.

 

[bigegg]

It's not even that simple.
all paints are, at least slightly, transparent.
The eventual colour will depend upon what's underneath it. - including how many coats of even the same colour.
Add to that, every batch of pigment will be very slightly different depending upon atmospheric conditions - temperature, humidity - when it's been made - even mixing time can make a difference.
Add to that that the laquer you put over the top may vary slightly in transparency and shade (some dry yellower than others), again depending upon temperature and humidity during manufacturing.
On top of that, not all pigments are exactly the same colour under every light.
You can mix "red" and "yellow" to make "orange" which will perhaps match perfectly in bright sunshine. It might look completely different under a street lamp, or a fluorescent bulb in a garage.

It *is* possible to scan a colour, and be given a start point for a recipe, but due to the above, the only way to make a perfect match is by eye, and one batch at a time.

 

[norsa]

2 things on top of those superb explanations. 1: metamorism. 2: im left handed so a met/mica will look different to that of a right handed painter as the particles lay in an opposite plane.

 

[steveo3002]

you can make the same tin of paint look differant by how its applied ...lash a metalic on really heavy and wet vs a light dust coat in a hot booth and they will differ

so while the machine can make a very good match , the mettalic bits need to sit the same hence the blending in most cases

 

[bigegg]

2 things on top of those superb explanations. 1: metamorism. 2: im left handed so a met/mica will look different to that of a right handed painter as the particles lay in an opposite plane.

The metamerism thing is what i meant about the "different colours in sunshine or under electric lights.

The second thing is new to me, and not something I would have ever considered.
I worked for years in a colour matching lab for a printing ink company, so all my colours were applied by roller rather than spray.
You live and learn! (or you don't live long)

 

[chunkolini]

If we lived in a Marxist-Stalinist state it would be easy.
We would have stuff called 'Paint'. You would be happy to buy it, it would be just what you need. if you were privileged it might be available in two colours, maybe more.
Variety is not the spice of life, decision making does my swede in.
Left handed paint? bejabbers.

 

[norsa]

I have of course got a left handed gun.

 

[ajlelectronics]

If we lived in a Marxist-Stalinist state it would be easy.

Errrmmmm.... ;-)

 

[El Donkey]

Thanks for explaining the factors. Any tips on knowing how close the colour mix is before you start? The reason I ask is that I have had some silver mixed by paint code and also taking in a small part of the car.

However, so far the colour is appearing lighter unless layed on very wet. So the lighter coated blend out area is showing up more.

What is the best technic to blend this out. I assume blending a silver that is slightly darker is easier than lighter?

Watching a few YouTube vids is using a 10/90 clear/reducer coat first and then blending in rather than out the way to go. I gather this helps to reduce the dry spray effect on the metalics in the bend area?

 

[steveo3002]

you need to make a spray out card , spray the card like you would the car including clearcoat ...then once its dry compare it in daylight

most blends , i would just cover up the repair area then for the last coat waft the colour away , run a tack cloth over it before clearing

 

[Seano]

An old painter I know has the addage that no matter how good you are, (and he is very) you have no control over what happens between gun and panel.

 

[pedrobedro]

I have had some silver mixed by paint code and also taking in a small part of the car.

Silver is the worst to try to blow in, although any metallic is a pain. It's easier to do a panel or work to a joint or swage line in the bodywork and easier to clear the whole panel than have a dry line to try to conceal. Dipping a flat blade in the paint, lift it and let it dry gets the colour something like a sprayed finish for a comparison. I find distance and pressure can make a difference in shade as well though I don't paint much these days so new paint technologies may have reduced this tendency.

 

[El Donkey]

I had made up a few cards and sprayed them with three different guns and one with a higher mix of reducer. There was a very slight difference in shade between the smaller jet and the 1.4 which I put down to wetter coats.

Anyway, I hit the car today. My first real attempt at doing some smart repairs.

Hard to say how successful I've been as its in a tent garage with no daylight and no space to stand back and observe.

 

[El Donkey]

Well, got my painting done, the colour is a shade lighter so had to prep a larger blending aarea. Wheels went back on this evening so tomorrow I will bring it out into the day light and see what kind of a job I have done :-) hoping it doesn't look like a silver giraffe!

 

[andyv]

If we lived in a Marxist-Stalinist state it would be easy.
We would have stuff called 'Paint'. You would be happy to buy it, it would be just what you need. if you were privileged it might be available in two colours, maybe more.
Variety is not the spice of life, decision making does my swede in.
Left handed paint? bejabbers.

This explains why in Cuba at least 50% of the cars are 50 years old and light blue.