I need to buy paint in a PS color code, how do I match the codes?

Try not to use HEX codes for real life colour references,

And as pointed out, different lighting conditions will change the colour regardless – Me and a buddy were developing an APP together, idea was that you could take a photo on your phone and the APP would give you a range of HEX numbers based on the image, just something for designers who see an interesting colour range and want to make a swatch or something.

Anyway, we quickly discovered the APP is flawed by its own merits if I took a photo of a piece of white paper at 9 am and then again at 11 am the lighting would be so different than the HEX code wouldn’t even be on the same spectrum.

Then we started thinking about how many different HEX numbers would actually show up on a piece of white paper at 9 am, does it display all the HEX numbers? It would probably be 50 or 100 different numbers or does it give you an average middle ground? Well, that’s not accurate…

As you can tell, the project came to a permanent halt.

TL;DR; lighting will affect the colour regardless, so the final colour mix doesn’t have to be 100% accurate, I’d say 80-90% accurate will suffice.

Why not take your buddy to the business so he can have a good look at the color you have in mind and take a picture?

(That idea might fall apart if he doesn't live in the area.)

Before you drive yourself up a wall attempting to match a very precise color, perhaps you should consider the environment of the final product: car panels or building sign. It will be seen on overcast & bright days and at various times of day and various levels of illumination -- with color temperatures that vary considerably and are beyond your control -- each changing your specified color. Instead, It might be more practical to take an array of actual paint color swatches, view them under a variety of outdoor lighting conditions, and then make your selection. A compromise.

Yes, there is one way to get a perfect color match regardless of the light source.

Perfect every time. I promise.

Just lower your standards.

Twenty or more years ago, I was at the hardware store watching the guy custom mix paint to match the customer’s nail polish. It wasn’t quite right, and he kept adding more color and was getting close by the time I got checked out in another line.

Keep in mind that if you go with a custom mix, you should get everything you need in a big container, because if you run out, you may never be able to do an exact match again.

Specifically:

...but unless you have a properly calibrated and profiled monitor, I have no idea how that looks on your screen. For all I know, you could see those two squares like this:

Color management was invented to deal with stuff like this. Put those numbers into a color space and you have a color - whether it's a standard color space like sRGB or Adobe RGB, or it's a unique and idiosyncratic color space like your monitor. They can all be defined by an icc profile.

Maybe you could make two adjacent Color Fill layers, one with #8410ea, and in the other click on "Color Libraries" and choose Pantone Coated. Then, browse through the Pantone swatches until you find one that works. On my system, 266 C looks pretty close. Although the auto painters would not be using actual Pantone inks, I think it likely they would have a swatch book to match to.

Hi

Color #8410ea also means nothing in Photoshop outside of the context of a specific Color Space. Those are just three Hex (base 16 ) numbers representing values of Red 132,  Green 16  and  Blue 234 . Those same numbers will look different in different color spaces e.g sRGB  Adobe RGB and ProPhoto.     Unspecified it is likely to mean sRGB but that is not guaranteed.

To mix the same color in car paints you will need to match swatches manually

Dave