Hmm. In our last house we painted the ceiling a really pale (matte) blue which I loved -- you could only see it was blue at certain times of day or if you were really looking for it next to the (white) crown moulding. In our current home most of the rooms are painted the same (albeit matte) color as the trim (which is a v. yellow cream), and the trim is in high gloss. In the kitchen the ceiling is 50% of the wall (a sheer grey-blue), but the crown in there is pure white (to match the cabinetry and wainscoting). In our dining room the wall, ceiling, crown, trim are all the same color, albeit different finishes. (The wall and ceiling are eggshell, the chair rail, panel & crown mouldings are satin.) I love it! not a great photo, but ... Here's another, clearer example (not from my home) of the trim being painted the same as the wall:

Thank you...i'll take a look at that one! I have so many samples now i think I've just over thought it too much!! House faces southwest, and have lots of large windows with it being a early 1900s home, tall ceilings, and I use mostly lamp light, not a big fan of overhead lighting as a primary source. Currently every room is painted a different color even though they are all open to one another, and I crave a blank slate to let colors in my artwork and textiles take focus.

As for diluting color . . . You cannot simply cut the colorants without understanding the base color and what the colorant is. Example. I have a can of paint here that has 4.25 / 32 Y3 Oxide Yellow 5 / 32 S1 Black 12.125 / W1 White 2.5 / 32 R3 Oxide Red in Base 2 If I cut the formula in 1/2 the white also gets cut in half and I will end up with a color that is darker, not lighter than the original formula. The computer systems are literally doing the math, but not all colorants are equal in strength - red it more transparent than most other colors, yellow is weaker than many other colors, so getting the mix right can be difficult. If you really want a lighter color that is between two shades it can be done, but I generally will buy a sample of the lighter shade and the darker shade and find out if they are both mixed with the same base. If they are in the same base you can play with the colors and mix the lighter and darker colors in different ratios until you find the perfect shade. I use syringes to measure the amounts so I am sure that the ratio is measured accurately. Then I do my own math to determine the amount of each colorant used in the samples and provide the paint store with the base color and the formula that has resulted in the color I want. If they are in two different bases you can do the same thing, but you will need to buy the appropriate amount of each paint and mix them together in a 5 gallon pail with an paint mixer drill attachment or ask the paint store to mix using their mixer. The same applies if you are trying to get a color that is just a tinge more green or yellow or blue than another. Tools like easyrgb have made a lot of this unnecessary - I can find a similar color in another brand and have it matched by my BM or SW paint store.

here is so much light in here that I might not lighten the 50%… Good call. Because 50% of what. Exactly. 50% lighter? 50% grayer? 50% whiter? 50% less blue? 50% less green? 50% of we could do this all day? When you change a formula, you create an new color. The new color might have similar attributes as the color you started with or it might not. Can't know what that new color will look like until it's mixed, dry and you can look at it (or measure it). If it works, great. If it doesn't, you own the can whether you like it or not. Wrote a blog post about it: https://thelandofcolor.com/cutting-paint-color-formulas-people-decide-it-works-before-its-done/