Yellow paint coverage.

[VinceFree]

Please help me here.

I'm trying desperately to convince both Hunbrol and Revell yellow paints that I want to cover the base coat (grey) in less than 20 coats with a brush.

2 coats with my airbrush does the job perfectly but 20 coats down the line with a brush and I can still see the undercoat.

Please dont tell me to stick with my airbrush - I want to learn how to brush paint in order to avoid acres of masking.

Please help me out

[JWM]

You have to dilute paint with adequate thinner, apply three times giving at least 12 hours (better whole day) between them. It could be good to use 1000 grain paper before applying on large surface (bottom of wings for example) , very gently, just to polish surface of previous coat. Use flat large brush (No 4, 6 or 8). Make move only once at given place. Be careful, if you dilute too much, the new coat can destroy (wash out) the previous one. So the perfect dilution is the key of success. 

Regards

J-W

 

[fubar57]

Yellow and red are a right b***ch to get right. Putting a white under-coat down first helps

[iainpeden]

Go to Halfords and get a yellow spray can.

[wellsprop]

9 minutes ago, iainpeden said:

Go to Halfords and get a yellow spray can.

 

This. 

 

I don't both brush painting white, yellow, orange and red. 

 

Much much easier to spray paint. 

[Toryu]

White primer or undercoat and matte yellow works well

[JWM]

This yellow tail was painted exactly like I described in previous (#2) post. 3 coats.

 

Regards

J-W

 

[bentwaters81tfw]

49 minutes ago, iainpeden said:

Go to Halfords and get a yellow spray can.

Every time. After over 60 years of modelling, this is the solution. Anything else is masochism.

White is a good primer/undercoat, but if you want depth of colour, spray yellow over black.

[malpaso]

I dunno about black, but I find a pink undercoat works well for yellow or red.

[Vlad]

2 hours ago, Toryu said:

White primer or undercoat and matte yellow works well

 

This.

 

But which Revell are you using? I recently started using Revell Aqua 15 and was amazed by the coverage. Almost single coat level coverage over white primer. But you need to get the thinning right.

 

Matt works much better, if you're using gloss yellows or reds find a matt alternative. Or at least get a solid coverage in the matt one first then final layer with the specific colour you need in gloss.

[Greg B]

So, what's this got to do with WWII aviation? Moved to the correct area......

[spruecutter96]

Three colours which nearly always create coverage issues: yellow, red and white.

 

I wish you luck in getting things as they should be. 

 

Chris.  

[TonyOD]

One of my current exercises in masochism builds has a yellow underside, I gave up trying to get coverage with brush-painted yellow enamel eventually, I sprayed it with Humbrol rattlecan 24. I use a very soft (8B) pencil to get a preshading sort of effect then paint over the while lot with a few thin layers of yellow acrylic (I tried overpainting with enamel at first, that didn't go well.)

 

The fuselage has just had the rattlecan treatment and I'll be getting busy with a pencil next.

 

I just did the wing leading edges on a 1/72 Spitfire in yellow enamel and it was a pain!

 

[Dunc2610]

Sorry to revive a 'thread from the dead', but is there any one brand of acrylic paint that has a 'better'/'easier to work with' yellow than the others, I use mostly Mr Colour paints, and their yellow mostly like using water when not even thinned and even if using a white undercoat.

[Mark Harmsworth]

1 hour ago, Dunc2610 said:

is there any one brand of acrylic paint that has a 'better'/'easier to work with' yellow than the others

I seem to remember (can't find it now though) that the problem with yellow paints is the quality of yellow pigment as compared to some other colours - so my belief is that achieving a decent coverage is a general issue. Having said that I'm dangerously out of my depth so I will now return to the shallows. Maybe this is something that a paint maniac could help with - @Casey maybe?

all the best

Mark

[Jamie @ Sovereign Hobbies]

2 hours ago, Mark Harmsworth said:

I seem to remember (can't find it now though) that the problem with yellow paints is the quality of yellow pigment as compared to some other colours - so my belief is that achieving a decent coverage is a general issue. Having said that I'm dangerously out of my depth so I will now return to the shallows. Maybe this is something that a paint maniac could help with - @Casey maybe?

all the best

Mark

 

You're close but it's not really a quality issue (implying that it could be done better) and simply that different pigments have different opacities and most bright yellow pigments are quite weak. Like most highly saturated colours though there's not a lot a paint manufacturer can do about it. Too much pigment to binder causes poor adhesion and can lead to chalking of the surface. Also, I don't mind sharing that one of the yellow pigment colourants we use - Quinoline Yellow - is the single most expensive one we need costing us £135 per litre for a good quality commercial product, with quality for our purposes not meaning opacity per se but each 1 litre can I pour into the cannister on our dispensing machine being consistent in its opacity such that there is some repeatability in the pigment formulae. With lower saturation colours much of the user's perception of opacity comes from e.g. white pigment with complex colours often having more pigment by volume of paint than simple colours might have. We try to keep pigment content to a certain proportion compared to binder but we can achieve a paint colour that one involves one pigment with less pigment in total than one which needs 4 different pigments, partly because of the minimum dispenseble amount. If it only needs a dot of black but the smallest the machine can accurately dispense is a dab, then you need to set the formula around the dab and scale up the other pigments to keep the proportions right. Generally though, that will be mitigated by making batch sizes that allow us to keep pigment to binder ratios about the same for all colours.

 

In summary then, the "best" brand of model paint yellow to work with is the one which has maximised the pigment content of the paint, but given the yellow pigment costs 7 times as much as e.g. carbon black does, few brands will add more of the stuff than is needed to pass the draw-down opacity check.

[Mark Harmsworth]

I knew someone would appear with better words on the topic than me. Sorry @Jamie @ Sovereign Hobbies - I should have thought of you. I suspect it was one of your posts that I was half remembering.

Mark

[Casey]

10 hours ago, Dunc2610 said:

but is there any one brand of acrylic paint that has a 'better'/'easier to work with' yellow than the others

As @Jamie @ Sovereign Hobbies mentioned - it is not only the pigment load but also the pigment itself. Coatings can be quite well represented by two properties: absorption and scattering (for simplicity ignore metallics, fluorescent, color shifting and other weirdos there :))

 

Lets imagine I can make a perfect yellow pigment. It absorbs 100% of all colors except yellow. That means it is also 100% transparent to all other wavelengths.

 

How would it look if I paint it over a white background with black line?

 

Black line would be still as visible as it was while the white part of background would only show in yellow spectrum range. It would look like black line on yellow - and it would not be opaque.

 

What is the best way to make such paint more opaque? Make it less perfect. Find a pigment that absorb other parts of light spectrum too, and add ability to scatter the rest of light exactly like this piece of frosted glass:

 

 

Interestingly, theoretically ideal white paint is also a perfect scatterer - it scatters 100% of light and absorbs 0%. Titanium white is quite good real life approximation.

 

Your choices are: add a tiny bit of red pigment which scatters non-yellow light color spectrum to make an orange tinted yellow which will be more opaque and feel 'so yellow it is almost orange', or just add white, or add matt agent which is scatterer too, or do all above. Or get it on white background first. There is no other way around that.

 

Edited January 30 by Casey

[PLC1966]

Games Workshop yellow always goes on well.  Suspect they are fairly heavy in yellow pigments so nippers can paint their overpriced figures with as little effort as possible.

[Casey]

13 minutes ago, PLC1966 said:

Suspect they are fairly heavy in yellow pigments so nippers can paint their overpriced figures with as little effort as possible

Or is matt heavy See my post.

[Bertie McBoatface]

47 minutes ago, Casey said:

: add a tiny bit of red pigment which scatters non-yellow light color spectrum to make an orange tinted yellow which will be more opaque

 

Is this why pink primer works so well to make a solid yellow? It makes sense. 

[Black Knight]

I prefer to use a gloss orange as a base coat for yellow

[John]

If you're an enamel user Humbrol 46 Orange is a good place to start for the undercoat. It sits in the space between golden yellow and orange and is, at least the tins I have, quite remarkably opaque. 

I've used it successfully as a base for orange, red and yellow top coats. 

 

John 

[Yes_Man]

On 30/01/2023 at 23:01, Bertie McBoatface said:

 

Is this why pink primer works so well to make a solid yellow? It makes sense. 

I was just going to say I always use a pink primer/first coat for yellows or light reds. Pretty sure I got that tip from a White Dwarf magazine donkeys ago for painting yellow Space Marines. Mr Hobby handily sell a pink Mr Surfacer these days too.

[Bertie McBoatface]

2 minutes ago, Yes_Man said:

I was just going to say I always use a pink primer/first coat for yellows or light reds. Pretty sure I got that tip from a White Dwarf magazine donkeys ago for painting yellow Space Marines. Mr Hobby handily sell a pink Mr Surfacer these days too.

 

I learned it from Goobertown Hobbies on YouTube. Mini painting + science!