Contrast, Speedpaint and Xpress: the one-coat paints, and what a match between them is worth

Three ranges sell the same trick: base coat and shadow in one pass. That trick is also why a colour distance between two of them promises less than the same number anywhere else on this site.

The comparison people want is a table: which Speedpaint stands in for which Contrast, which Xpress Color replaces which of either. This site will give you that table — every Citadel to Vallejo pairing and the rest are on the charts, matched the same way everything else here is matched. Before you buy off one, it is worth knowing that these particular ranges break an assumption the number quietly makes about the paint underneath it.

What the three ranges actually share

A one-coat paint is a heavily tinted, transparent medium engineered to keep moving after the brush leaves. Surface tension pulls it off the raised surfaces and gathers it in the recesses, so a single pass leaves a base colour and a shadow at once, following the geometry of the model instead of your brush control. That is the whole product. Citadel sells it as Contrast, The Army Painter as Speedpaint, Vallejo as Xpress Color and Scale75 as Instant Colors, and there are others. Where each of them sits in the rest of its maker's line-up is in paint ranges explained.

They are not the same paint and nothing here says they are. The ΔE column compares the colour values on record for each pot, which is a real comparison and a narrow one. Every property that makes this class of paint fast is also a property that makes one colour value a worse description of what is in the pot.

The colour is a spread, not a point

An opaque paint applied properly gives you one colour across the surface. A one-coat paint is designed not to. On a single pass over a single shoulder pad it reads pale on the crest, mid on the flank and dark in the crease, and all three are the paint working correctly. A hex value, or the Lab triplet behind it, is one point taken out of that spread.

So when you compare two of these to each other, you are comparing two points that each stand in for a different spread. Two pots can carry nearly identical colour values and still land differently on a model: same average, different distribution. The average is what the number sees. The distribution is what someone sees from across the table.

The undercoat is half the recipe

Transparent means whatever is underneath is showing through. These ranges are made for a light neutral undercoat — bone, off-white or pale grey, depending on the range and what its maker recommends — and the undercoat is not a preparation step, it is an ingredient.

Over a white or bone base you get the brightest, most saturated version of the pot. Over a mid grey the same pot reads darker, duller and lower in chroma. Over a coloured base you get a mixture of the two, which is often a good colour and is not the one on the label. Nothing about this is a defect; it is the control the range gives you.

It does mean something specific for matching. A published colour for a transparent paint describes one application over one undercoat, and switching undercoats will move that colour further than most cross-brand matches ever move it. A match between two one-coat paints is only a match if both go over the same undercoat. Match the published values of two ranges that assume different undercoats and you have matched two things that will not both exist on your model.

A second pass is not a second coat

With an opaque paint, a second coat is the same colour more solidly. With a transparent one it is more pigment sitting in the same place: darker, more saturated, and further from where you started. That is useful — you can deepen a recess by going back into it alone — but it means a difference in pigment strength between two ranges is a difference in colour, not just in convenience. A pot that needs two passes to read the way its swatch reads will not sit where a one-pass pot sat.

What the number is worth between two of them

Less than the same number between two opaque base paints. Four things stack up:

The two values may not have been produced the same way. Undercoat, number of passes, the surface it was painted on. Every colour sample carries some of this, as what a hex code misses goes through — but for a transparent paint those conditions move the result far more than they do for an opaque one.
Same colour, different flow. How hard the medium pulls into a recess sets the contrast between crease and crest, and that contrast is most of what reads on a finished model.
Different pigment strength means a different number of passes, which by the point above means a different colour.
Different working time. How long you have to move it, and what happens when you go back over an edge that is already down, differ between ranges. Some formulations in this class can re-wet under a later wet coat, so whatever you are testing, test your varnish over it too.

The practical consequence is the same one that applies to metallics: treat a cross-range one-coat match as a shortlist entry, not as a decision. The ranking has narrowed the field honestly. It has not finished the job.

When the swap holds up anyway

Often enough to be worth doing. It holds up best when:

The area is large and simple. A cloak, a tabard, a banner, a vehicle panel. There is little recess geometry, so the difference in distribution has nowhere to show itself and you are back to comparing two colours, which is what the number is good at.
Something goes over it. If the one-coat pot is a base for a drybrush or an edge highlight, the layer on top takes over most of the final appearance and absorbs a lot of drift.
You control the undercoat and the passes. Same primer, same number of passes for both candidates, decided before you compare them.

It holds up worst on fine geometry — chainmail, fur, cabling, ribbed cloth, rope. That is exactly where this class of paint earns its money, and exactly the behaviour a single colour value does not carry. It also holds up badly for an army's signature colour, for the reason set out in substituting a paint: there the property that matters most is whether you can still buy the pot in a year.

How to test one against another

Five steps, and the first one is the one people skip:

Test on something with recesses. A spare shoulder pad, a scrap of textured plastic, anything with a crease. A flat swatch card hides the only difference you are testing for, and it will tell you the two paints are identical right up until they are on a model.
Same undercoat on both halves, and the undercoat you actually use.
One pass each, same brush, same load, then stop. Compare what one pass gives you, because that is the promise the range is making.
Let it dry completely. Acrylic media are milky wet and clear cured; a wet comparison is not the comparison you care about.
Varnish it the way you varnish models. A matte coat flattens the specular difference between crest and recess, which can pull down the very contrast you chose this paint for — and re-wetting, if the range does it, is much better discovered on a scrap.

Using this site for it

Look inside the same range first. A neighbouring colour in the one-coat range you already own keeps the medium, the flow and the undercoat constant and moves only the colour — which is the single variable a number can actually settle. Every paint page here ends with the nearest colours inside the same brand for that reason.

If you have to cross, and especially if you are moving a whole recipe rather than one pot, open the chart for the pair of brands and take the whole set out of one range, so the swaps stay consistent with each other. If what you are starting from is a colour rather than a pot, search by hex code — remembering, now, that a hex code for a transparent paint is a claim about an undercoat as much as about a pigment.

And read the ΔE as what it is. How close is close enough sets out the brackets; this class of paint is the case where the bracket needs to be tighter than the job alone would suggest, because the number is answering a smaller part of the question than usual.

Put it to work: find a paint from a hex code, open a conversion chart, or browse every range.