Satin finish on humborl matt

[Spearjig]

Using humbrol enamels for the first time on a project. on the whole Im having no problem except for the cleaning of the airbrush ( no big deal) However after stirring and stirring one of their colours and applying it Im getting patches of satin instead of matt ( hopefully a clear matt coat at the end will fade this down.) However whats causing this, not thinned enough , to much in one coat or too higher pressure in the brush?

[JamesPerrin]

Uneven airbrushing can lead to variations in the finish. eg if spraying a gloss coat it needs to go on 'wet' to produce a gloss finish, if you have too much air or too far away it will dry before hitting the model and produce a matter finish. With a matt enamel I wouldn't expect you to get shinier patches but rather even matt'er ones.