Isolating Medium


Non-reversable, oil-based medium formulated to even-out the reflective finish of the painting prior to varnishing.

It dries to a non-yellowing, gloss finish to protect and enrich oil paint surfaces, especially those that are dull or matted-out due to being underbound as a result of poor priming or solvent-overthinning of the oil paint.


Stand Oil (40 Poise), Distilled Gum Turpentine, Cobalt Drier.

Product Application

Langridge Isolating Medium is a Stand Oil based fluid medium for the isolation of preceding paint layers.

It may be applied to paintings once the existing paint film is stable and dry.

After application of Isolating Medium the paint surface will have an even gloss reflection.

Isolating Medium is non-reversable and is NOT a final picture varnish.

It’s function is to create a permanent layer that evens-out a paint surfaces’ reflection prior to application of a fully reversable artist’s picture varnish or subsequent paint layers.

After Isolating Medium is applied 3-6 months must still be observed before the application of a final picture Varnish.

Although it may sound counter-intuitive if wanting a matte finish on the painting, it is far easier to get an even final reflective finish if varnishes are applied over an even ‘gloss’ paint surface. 

Langridge Isolating Medium has a high Stand Oil content and, as such, is a ‘fat’ medium. 

It should only be used as the final layer unless succeeding layers of oil paint are mixed a minimum of 1:1 with a Langridge ‘Fat’ Painting Medium.

Dries to a gloss finish.

How to apply Isolating Medium to a painting

Lay the painting flat, face up, on a table. Position it so you can see light reflected from its surface.

Pour some Isolating Medium into a clean cup. Load a clean white lint-free cloth or rag and squeeze out any excess.

Begin application at one corner of the painting, working in a circular motion across the whole painting. Work quickly so that the surface receives as thin and even coating as possible. Working quickly and deliberately, since the medium will set quickly, proceed in a systematic way across the surface of the painting. Check the work against the light from time to time to be sure all parts of the surface are receiving an equally thin coating.

After the entire painting has been coated, allow it to sit for about 60 minutes before removing it from the table, then lean the painting against a wall, face in, to finish drying. Dust in the air cannot settle on the surface of the painting leaning face in, but be careful not to stir up any dust on the floor in the vicinity of the painting.

Discard any working medium left in the cup. Working Isolating Medium should be considered contaminated and should not be returned to the stock bottle.


For best results thin with Distilled Gum Turpentine. However, Artists White Spirit or Langridge Odourless Solvent may be substituted. 


Langridge Isolating Medium is a pale amber colour liquid with characteristic Gum Turpentine odour.

Very fresh medium may exhibit a green cast. The colour of the medium will not effect the oil colours over which it is applied.

Clean Up

Clean brushes with any artists’ solvent (eg Gum Turpentine, Low Toxic Solvent, etc.).

For further washing apply a small quantity of Marseille or other pure olive oil soap and massage the bristles of the brush to release any remaining colour. Wash thoroughly in warm water. Leave to fully dry before using for oil colours.

Drying Times

24-48 hours to touch dry. Any airflow over the surface will evaporate the solvent more rapidly which will reduce drying times.

Full film drying 3-6 months

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