You mention the DM42 … The interesting point is that we did not have chance to influence the DM42 and if we had, those x<>y arrows would have been edited, and the stroke thickness of the white letters beefed up. It seems (to me) that the white strokes is the only part of my DM42 that looks a bit Chinese.
As I said, it is pretty, and pretty good. I think maybe some minimal tinkering is needed to get it to what you want it be. So, as food for thought, my comments which you need to apply to how you want it to be, not how I want it.
About the interesting font choices, the only criticism: I think lg and ln are the only glyphs that show the very curly serifs. IMO, it stands out in a way that it draws attention to it, in the wrong way. I am not criticising a cursive font, but I think these L’s need their protrusions clipped by maybe 30%.
I think the spaces between golds and blues are a bit too recipe like, and with the short labels aligned with the button edges, it shows. It needs balance, i.e. the labels need to be shifted until balance by eye is found. An extreme example is the space between ⍺ and √x.
All the lower case yellow and blue letters, as well as the blue ⍺, √x, and 𝝿 appear a lot smaller than the upper case and digits (like 10). The small x exponent at 10^x is even smaller. The ratio (size of X)/(size of x) of a given font is normally maintained between upper case, lower case and digits. But in this device I think clarity should be more important than the strict rules of the proportions of a font. I would suggest you upsize the smaller letters to be closer to the visual impact of the larger letters. The brain needs only a small variance in shape, while the eyes need bolder and larger letters.
I made an illustration to show the impact of size. I used the default font on my laptop (Neue Haas Grotesque Pro) and with that font choice I am not at all commenting on the font selection (except with lg and ln above). The sole purpose of the image below is to show impact of the same font with varying point sizes and spacing, as tweaked for each individual label within the space around it.
Square root x: In the font tool that I think you use to maintain the calculator fonts (Fontcreator), there is a way to import a scanned or otherwise created bitmap and convert that to a vector font. You could try make a sqrtx glyph and edit it in Fontcreator to have a vector glyph, then you won’t have to manually insert a line.
Apart from the division slash which seems a tad long and the said arrows that may need a diet, the large white labels are nicely done. The stroke width of the glyphs are important and I would still look at tweaking:
- the positioning of the 1 and the x in [1/x] could be closer and more compact,
- the relative sizes of the x in [y^x], [e^x]. Check if you cannot gain a point size or two on the x, also shifting a little closer. It will do a lot for the impact. The exponent needn’t be much smaller and much higher.
- 2, x and y in x<>y and x^2 seem bold enough.
I do think f and g can be a point size fatter and maybe check and see how it looks if f is positioned a slither lower and g a slither higher. They need not be aligned as if on paper, but stand on their own on their buttons.
Just try these suggestions and see for yourself if it makes a difference. Ignore them all if it doesn't.
At this stage the only changes you can make are these kind of small edits, and not all of them will work for you.