Hey Antti! I've come across this same conundrum. Depending on your setup, you can change the color space of your drawing tablet in your system settings to see if you can get the tablet to match another computer monitor color space more closely. That said- phone screens have much higher contrast ratios than computer monitors so it will be tough to match exactly. The color checkers out there are a good solution to match your tablet screen to other computer monitors, but they may not get as close as you want to a phone screen. I'd worry that setting your tablet colorspace too far to match a phone may skew the values you're seeing on your tablet which may mess with your value judgement. If your work flow demands color accuracy to a high degree, you might want to first check out a color accurate monitor before investing in a color checker (BenQ and Asus ProArt monitors offer professionally calibrated color gamuts) but the color is still slightly different for me even on a Cintiq Pro and an Asus calibrated monitor. The solution I came to was to try to get my monitor and tablet as close as I could to one another, and then if needed check stages of my work on a phone or mobile tablet device throughout the process to see how things look in each environment. Ultimately you'll find a good balance of what works for you. Best of luck!