Does water-based polyurethane affect paint color?

Question

I recently painted a dresser. I originally painted it a darker gray than I wanted so after putting the initial two coats on I took the paint back to Home Depot and had them lighten the rest of the gallon for me. The paint was not tacky at this point in the process. After applying the additional two coats the finish product is tacky. I'm pretty sure my mistake was too thick of an application on the last two coats. I thought the sheen was better with thicker coats...

Now that it is tacky I'm considering applying a water-based polyurethane to help with the tackiness and give additional protection.

I'm just concerned with the polyurethane affecting the color of the dresser. Have you found that water based polyurethane affects paint color?

Answer 1

If the paint is gloss¹, no. If the paint is matt², yes. For sheens in between the effect will be somewhere in the middle.

If in doubt do a test on some scrap, or on an inconspicuous spot of the project piece.

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¹ Note however that a gloss paint might require you to dull it down to ensure good adhesion between the paint and the overlying clear finish. If the paint and clear finish are of similar chemistry (both oil-based or both waterbased) and the paint was applied fairy recently this isn't likely to be necessary. But in the case of older paint, that has had a chance to fully cure, this is highly advisable in all cases. You can dull the paint down by lightly sanding, scuffing with fine steel wool or a nylon abrasive, or using a liquid deglosser.

² The colour will appear darker with a slight increase in saturation (obvious sometimes but not always, depending on the original colour). Or, as commonly said, the paint will look "deeper".