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Changing colours mathematically

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Luzern
Hero
Posts: 4,574
Thanks: 800
Fixes: 8
Registered: ‎31-07-2007

Changing colours mathematically

How would the photobrains set about this? Is it possible?

I have identified with the colour picker the rendered colourcodeof an object as RGB 52 60 33. The true RGB code is  123 249 247. The slide on each colour on the channel mixer is set to its max 100.

Does anyone know how to use the sliders on the mixer to adjust from seen to real colour, seeing as colours are scaled in HEX, but the slider in DEC?

No one has to agree with my opinion, but in the time I have left a miracle would be nice.
9 REPLIES 9
Mook
Grafter
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Registered: a month ago

Re: Changing colours mathematically

@Luzern Where are you getting this information from? There is a huge difference in value (and therefore colour) of the two RGB values you quote.

VileReynard
Seasoned Champion
Posts: 12,065
Thanks: 515
Fixes: 18
Registered: ‎01-09-2007

Re: Changing colours mathematically


@Luzern wrote:

I have identified with the colour picker the rendered colourcodeof an object as RGB 52 60 33. The true RGB code is  123 249 247. The slide on each colour on the channel mixer is set to its max 100.

Does anyone know how to use the sliders on the mixer to adjust from seen to real colour, seeing as colours are scaled in HEX, but the slider in DEC?


It's unusual to quote individual components in hex - but you might quote a colour as e.g. #FA89FF.

123 decimal = 7B hex

249 decimal  = F9 hex

247 decimal = F7 hex

So your "true" colour could be written as #7BF9F7

Weird program you are using...

 

"In The Beginning Was The Word, And The Word Was Aardvark."

wisty
Pro
Posts: 553
Thanks: 95
Fixes: 7
Registered: ‎30-07-2007

Re: Changing colours mathematically

The colour codes give colours which are a long way apart - see attached.

The top row of digits are decimal, the borttom row are the hex equivalents. The two colors you mention are at the extremes.

Are you sure the colour picker is getting the colour you want. many colours on screen are "dithered" with adjacent pixels being different colours to give the shade desired. Try the colour picker on different pixels in the same area.

What program are you using?

Luzern
Hero
Posts: 4,574
Thanks: 800
Fixes: 8
Registered: ‎31-07-2007

Re: Changing colours mathematically

I'll come back later once I have another photo that is true colour for an element in the one I am playing with.

No one has to agree with my opinion, but in the time I have left a miracle would be nice.
Luzern
Hero
Posts: 4,574
Thanks: 800
Fixes: 8
Registered: ‎31-07-2007

Re: Changing colours mathematically

It seems the other info is not available.

@Mook @VileReynard 

I manage to type the values I got from the colour picker wrongly, but by as little as 2 under what was intended in one of the  figures.

Yes I agree that there is a vast difference in the values from the picker, but I got the code for the true colour from https://rgbcolorcode.com/color/electric-blue The colours of the photo are indeed up the creek.

My program is Photoplus X7 that is not too dissimilar from Photshop. 

No one has to agree with my opinion, but in the time I have left a miracle would be nice.
Mook
Grafter
Posts: 42
Thanks: 37
Registered: a month ago

Re: Changing colours mathematically

Depending on where you were out by two, may or may not affect the actual colour, for example, if it were say 54 instead of 52 then no huge difference but if it were 72 or 32 then yes these are obvious changes of colour.

So to clarify @Luzern, what exactly is it you are trying to achieve here?

wisty
Pro
Posts: 553
Thanks: 95
Fixes: 7
Registered: ‎30-07-2007

Re: Changing colours mathematically

Assuming you are trying to correct a photo of something, Then the most likely explanations for the error are

a) the white balance of the photo is off due to the lighting conditions when you took the picture. Photo Plus ( Photo Fix tool, White balance filter) wil let you adjust the white balance for the image. I usually use the colour eyedropper on something in the image known to be white, then play with the adjustments until it shows up as white (0,0,0).

b)As I said earlier, it may be that the  .jpg you are trying to adjust has dithered the colour to get an accurate impression of the colour. Camera sensors and displays only have three colours (red, green and blue) to get intermediate colours they dither the pixels so that the eye sees the composite of the three. It may be that the specific pixel you picked up with the eyedropper is one of the colours that have been dithered. Expand ( Zoom in) the image until you can see the individual pixels, and use the eye dropper at that resolution.

c) Where did you get the information that the colour you are looking for is Electric Blue. Electric Blue may not be electric blue - see attached. I looked it up on a colour standard website https://rgb.to/keyword/7446/1/electric-blue.

The pantone colour seems to be called Electric Blue lemonade, and doesn't actually appear on that swatch.

 

VileReynard
Seasoned Champion
Posts: 12,065
Thanks: 515
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Registered: ‎01-09-2007

Re: Changing colours mathematically

I don't understand these things - but not all colours can be expressed as a RGB value.

The word to search for is "colour gamut".

See https://en.wikipedia.org/wiki/Gamut#Representation_of_gamuts 😎

"In The Beginning Was The Word, And The Word Was Aardvark."

Luzern
Hero
Posts: 4,574
Thanks: 800
Fixes: 8
Registered: ‎31-07-2007

Re: Changing colours mathematically

It's been an interesting exercise. I shall leave it there for the particular photo.

No one has to agree with my opinion, but in the time I have left a miracle would be nice.