Can anyone tell me which paint will be absolutely flat. There is no paint industry standard for gloss or sheen. It's the subjective names that brands give to their different finishes that cause the confusion. For example... WTH is "pearl". WTF is "delicate". And so on. Generally speaking, however, paint brands follow the same-ish process to ascertain gloss levels of their paints. Remember, however, we cannot confirm that all the data was obtained exactly same way brand to brand so the comparisons you make are at best an ESTIMATED GUIDELINE of gloss levels. But, hey, a guideline is better than nothing. So, here goes: First thing you need to know is gloss is measured in units. It's called Gloss Units and you'll see it referenced as GU. Gloss units, GU, run on a scale of 0 GU to 100 GU. 0 is dead flat, 100 is ridiculous-mirror-like shiny. Find the GU for the brand/grade of paint you want to use on the paint can label or Google the Technical Data Sheet (TDS). Here's one for PPG's Manor Hall Flat . Here's what it says about Manor Hall Flat - SHEEN: Flat: 0 to 5 (60º and 85º Gloss Meter). The 0 to 5 is the Gloss Units (GU) and it goes on to tell you that measurements for those GU's were done at 60º and 85º. Measurements are done at a 60° angle, an 85° angle, or both. 60° applies across the board and is most common. 85° is used for the low-gloss end of the sheen spectrum because of math. One might say it (85° angle) helps to dissect units of flattness into smaller bits so they are easier to discern. Now you know how gloss is measured and why the confusing, subjective finish names are not consistent across paint brands. Now you know of two places where to find Gloss Unit (GU) information for the brand/grade you want to use. Now you know why you will see measurements at 60º and 85º. And that 85º speaks to the lower-gloss end of the sheen spectrum. What you need next is some context for the Gloss Units you now understand and know where to find. So you need a table. And here it is from the Mater Painters Institute, MPI. They got rid of the subjective finish names that paint brands made up and created this table of Gloss Levels 1 to 7 based on Gloss Units (GU). Gloss Units that all brands use to measure gloss and sheen. Hope this table from MPI helps you find the flattest flat finish out there.

Interior finishes are all the materials/surfaces inside the envelope. ie: flooring (ceramic tile, carpet, hardwood), ceiling, wall paneling, drywall. Exterior Finishes are all the materials/surfaces outside the envelope, and are in contact with the elements. ie: asphalt shingles, siding, bricks, stucco. I consider paint to be a protective coat of interior or exterior materials, like drywall or metal. It also adds color.

You can keep window and mullions as is and paint the trim. It’s a good look, IMO.

Great thanks for that and very quick reply :), was many whites for Metropolitan and was not sure. this is great , a second close option is --BM: Thunder (flat) on walls Trim and ceiling (unknown yet) would semi gloss B.M Oxford white for Trim and Oxford white flat for ceiling work? If ithese colors work, would it be possible use a different color on the coving/cornice ? So leave flat oxford white on ceiling , flat Thunder on walls and have cornice/coving between wall and ceiling a different colour to wall and ceiling if so any suggestions? Or would it look better have the ceiling and the trim and cornice/coving the same color? Thanks again.