Different Shades of Colour

middleman666

Hey people,

I have a question about colour shades...

Say I had a system that lets a user pick a colour using HEX and then I wanted to search a database for that colour, or the closest shade to that colour.

Is there some sort of php function I can use that will display all the shades of one colour? or would I have to write out a list of HEX values closest to that colour?

Any information of this would be very welcome 🙂

thanks.

Weedpacket

You can parse the hex code into an RGB triple, convert the colour model from RGB to HSB, then play around with different saturations and brightnesses (changing the hue ends up changing the colour) - making a gradient of saturations from 0 (grey) to 100, say - then convert back to RGB.

NogDog

Not sure what you mean by the "closest to that colour". Wouldn't the "closest" be that exact hexadecimal value? Or are you referring to the closest so-called "web safe" color (#336699, CCFF99, etc.)?

PS: I don't know if this would be of any help, but here's a page I created a little while ago as a sort of prototype of something I was thinking about then (but haven't pursued since then). It might give you a few ideas. (I've included the source code on the page itself.)

middleman666

thank you both for your replies.

I think I understand what your trying to say Weedpacket and I will try it out soon.

Make HEX value from database to RGB
Make RGB to HSB
Create an array of colours with different saturations and brightness by increasing or decreasing these values at the same rate.
Change to RGB array
If the hex value the user entered (converted to RG😎 is in the array (gradient) of colours that was created from the HEX value in the database then the colour the user picked was close enough to that colour.

Does that sound right?

I haven't yet tried increasing the saturation and brightness via php, but I done it in an image program (Fireworks 8) and I see that if you increase both the saturation and brightness at the same time you get different shades of that colour. Trouble is, if you increase or decrease the brightness too much, you end up with black or white - of course, this would happen with every colour so would you recommend I stop the increase and decrease at say 50 each way?

by "closest to that colour" I mean closest to that shade of colour.