14 Differences Between Paint and Primer

Paint and primers go hand in hand. Not everybody knows the exact difference between them. Even more, some people ask whether there’s any real difference between primer and paint, especially since they can look similar at a first glance.

Primer is white and it seems to be just as good as white paint. There are differences in how these coats are applied and considerable purpose differences.

The main difference between primers and paints is their purpose. Primers are made to bond to an unfinished surface and to make paint stick better to that surface. Paint is a finishing coat that adds pigmentation and durability to the painted surface.

Primer is mostly made from synthetic (bonding) resins while paint is dominated by pigmentation additives alongside fast-drying and protective additives.

Paint and primer go hand in hand. Paint that comes with included primer is called self-priming paint.

But what makes primer what it is and paint what it is? Here are all the major differences you need to know about.

1.     You apply primer before paint

Primer is the first coat you apply to an unfinished surface. The resins in primer stick to the unfinished surface better than directly painting over it. These resins also bond to the later-applied paint better.

In short, primer is applied to an unfinished surface to make paint stick to it better.

You can apply primers on all surfaces you plan to paint. This includes drywall, wood, plastic, and even metal.

There are different types of primers that can be used for different materials.

What surface needs priming?

  • Walls
  • Drywalls
  • Ceilings
  • Wood
  • Metal
  • Masonry

2.     Paint sticks to primer better than directly to the painted surface

This leads us to the second most important difference. Paint adherence or the way paint sticks to the surface is different compared to how primers stick to that same surface.

The primary role of primers is to act as a glue or an agent that sticks to surfaces and that paint sticks to better. Paint has many other purposes including protecting the surface from UV lights and mildew.

3.     Paint and primer can be mixed in self-priming paint

More of a characteristic than a difference, the fact you can mix primers and paint speaks about quality paint and easy application.

Most types of paint that are applied in one coat only are self-priming paints or paints that already have primers in them.

This mix is applied as regular paint as a finishing coat and it needs to look great.

4.     Primer is made from synthetic resins (and sometimes plastic)

Various types of resins or even direct plastic is used in primers to make the paint stick to this preparation coat.

Resins are sticky by their nature. Even touching the primed surface with bare hands should show your skin slightly sticky to the primed surface.

These resins of primers are good at evening out uneven surfaces as they are more forgiving than paint.

5.     Paint has pigment

The advantage of paint of primers is pigmentation or coloring. Paint has complete pigmentation which means it adds color to a painted surface. Primers are mostly white (sometimes gray) and almost transparent in nature.

Pigmentation is added to primers just so you see the area you’ve already applied it on and not to color a surface. This is why full pigmentation is not added to primers. Most primers look slightly transparent as a result.

6.     Paint has (finishing coat) additives

Paint is has a more complex formulation as it has multiple other purposes aside from adding a top coat of pigmentation. Additives in paint are used for different purposes.

  • for durability
  • for faster-drying
  • for sheen
  • for combat mildew

All of these additives are only present in paint and not in primer. Some exceptions apply for additives that are made to dry fast.

7.     Paint comes in different finishes

As a top coat, paint comes in multiple finishes. All of these finishes give paint a different aspect which doesn’t happen with flat primer.

The most common paint finishes are categorized as follows.

  • Matte (flat)
  • Satin
  • Eggshell
  • Semi-gloss
  • High-gloss

All of these finishes are made by adding additives that primer doesn’t have or which primer doesn’t need.

8.     Paint is applied in lesser amounts over primer

The amount of paint you add to a surface is directly proportional to the primer you’ve applied to it. A surface has higher saturation levels when you apply primer first, alongside having better adherence. Paint sticks better and in lesser amounts on primer as a result.

One of the differences between paint and primer is that the applied primer is mostly the same on certain surfaces such as walls while paint application varies according to how well it covers an area by pigmentation.

9.     Primers even out uneven surfaces

Primer can also be seen as a preparation layer for paint. It makes paint stick on areas it wouldn’t stick as well otherwise.

Primer sticks to all types of surfaces, even those paint has a difficult time sticking to easily. This leads to primer covering up many types of uneven surfaces better.

10. Primers can stop stains from reaching topcoat paint

There are multiple types of primers for multiple types of surfaces made today. Some of them have stain-blocking capacity. This means stains don’t reach the paint coat for a better paint result.

Primers can stop all types of stains such as those resulting from water infiltration. The benefit of such primers is they block stains regardless if the paint has the capacity to block stains in its role or not.

11. Primers are more expensive than (most) paint

Good primers aren’t cheap. In fact, good primers can cost more than the average gallon of paint. Premium primers are cheaper than premium paint, but many types of premium paint are already self-priming. This means primers can be more expensive than paint.

12. Primer isn’t UV resist (it yellows)

UV resistance is specific to very good paints, especially those made for exterior use. UV resistance is added to paint through additives. There’s no UV resistance in primers. This is why a standard primer can yellow or become off-white with time when exposed to dirt and sunlight.

13. Paint is washable

Primers aren’t washable while many types of paint are washable. You can wash your painted walls, wood, or metal surfaces which can keep them looking clean for a long time. Primers can’t be washed.

14. Primer is slightly transparent

You can’t use primer as paint as most types of primers have reduced pigmentation which makes them fully or partially transparent. Applying multiple coats of primer may eventually color a surface sufficiently to be confused with a layer of paint from a distance.

FAQ

Is primer just white paint?

Primer can have an almost full-white color but it isn’t paint. It doesn’t have the finishing pigmentation and durability additives paint has. Primers have a bonding or adherence purpose.

How long can I live primer unpainted?

The best paint adherence is seen just a few hours from applying primer. Some manufacturers allow up to 30 days break between primer and paint application on walls as dust tends to settle and stop perfect paint coating.

Do I need primer if my walls are white?

Primer isn’t always necessary on the surfaces you paint regularly (every 2-3 years). However, primer limits the amount of paint you apply which means it also allows for cheaper painting.

Is primer waterproof?

Primer may or may not be waterproof. It will stop direct contact of water or moisture with a given surface but it doesn’t have the protective additives some types of paint have.

How many coats of primer do I need?

Surfaces without previous painting or priming may need up to 3 coats of primer to be fully covered. This ensures total pain adherence as a single coat of primer may overlook uneven surfaces or leave bald patches on the surface about to be painted.

Is primer cheaper than paint?

Primer may be cheaper than paint but good primer is more expensive than cheap paint. Expensive paints can be self-priming. Self-priming paint can be cheaper than good paint and good primer purchased separately.

Which is more important – primer or paint?

A good primer is crucial for a proper paint job. Regardless of the surface, you’re painting on, primers manage to ensure even paint coverage and can sometimes lead to great results even with average paint quality.

Read more about paint on Wikipedia

Read more about primer on Wikipedia

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