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Newbie : How are these different in adjusting the colour of the pic.

Thanks

ABC
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ABC wrote:
> Newbie : How are these different in adjusting the colour of the pic.
>
> Thanks

In most photo-editing programs you can adjust the relative amounts of red,
green and blue in the image. All of the functions you mentioned do
basically the same thing, and alter the amount of R, G or B to achieve a
particular effect, and the different names refer to different ways of
making the adjustment.

Colour temperature, for example, only has two controls: soure colour
temperature and display colour temperature, and it /basically/ keeps the
green constant whilst either increasing red and decreasing blue (to make
the picture "warmer" - to look more like sunrise or sunset), or vice-versa
to make an artificial light picture look more like daylight.

I suggest you search for a good tutorial on the Internet, or find a book
in your local bookshop about using e.g. Paint Shop Pro.

Cheers,
David

In message <>,
"David J Taylor" <david-> wrote:

>In most photo-editing programs you can adjust the relative amounts of red,
>green and blue in the image. All of the functions you mentioned do
>basically the same thing, and alter the amount of R, G or B to achieve a
>particular effect, and the different names refer to different ways of
>making the adjustment.

True, except the hue. While the other just scale the RGB channels, a
hue change actually will change the colors in such a way that is
irreversible. Two different hues can become the same hue after a hue
adjustment. Hue adjustment can result in 255 in a channel that
originally had 0.
--

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John P Sheehy <>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

wrote:
> In message <>,
> "David J Taylor" <david-> wrote:
>
>> In most photo-editing programs you can adjust the relative amounts
>> of red, green and blue in the image. All of the functions you
>> mentioned do basically the same thing, and alter the amount of R, G
>> or B to achieve a particular effect, and the different names refer
>> to different ways of making the adjustment.
>
> True, except the hue. While the other just scale the RGB channels, a
> hue change actually will change the colors in such a way that is
> irreversible. Two different hues can become the same hue after a hue
> adjustment. Hue adjustment can result in 255 in a channel that
> originally had 0.

I regard Hue adjustment as rotating things round a colour circle, and
therefore as something which should be reversible. Depends on which
program does the adjustment? My perception probably comes from too much
involvement in colour TV!

David

David J Taylor wrote:

> wrote:
>
>>In message <>,
>>"David J Taylor" <david-> wrote:
>>
>>
>>>In most photo-editing programs you can adjust the relative amounts
>>>of red, green and blue in the image. All of the functions you
>>>mentioned do basically the same thing, and alter the amount of R, G
>>>or B to achieve a particular effect, and the different names refer
>>>to different ways of making the adjustment.
>>
>>True, except the hue. While the other just scale the RGB channels, a
>>hue change actually will change the colors in such a way that is
>>irreversible. Two different hues can become the same hue after a hue
>>adjustment. Hue adjustment can result in 255 in a channel that
>>originally had 0.
>
>
> I regard Hue adjustment as rotating things round a colour circle, and
> therefore as something which should be reversible. Depends on which
> program does the adjustment? My perception probably comes from too much
> involvement in colour TV!
>

It's fully reversible in PS CS via an adjustment layer.

--

John McWilliams

In message <>,
"David J Taylor" <david-> wrote:

>I regard Hue adjustment as rotating things round a colour circle, and
>therefore as something which should be reversible. Depends on which
>program does the adjustment? My perception probably comes from too much
>involvement in colour TV!

Photoshop's hue/saturation control will shift red to blue and leave blue
where it is, for example.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

wrote:
> In message <>,
> "David J Taylor" <david-> wrote:
>
>> I regard Hue adjustment as rotating things round a colour circle, and
>> therefore as something which should be reversible. Depends on which
>> program does the adjustment? My perception probably comes from too
>> much involvement in colour TV!
>
> Photoshop's hue/saturation control will shift red to blue and leave
> blue where it is, for example.

Oh, in which case it's not operating how I would expect a hue control to
operate. To me, hue is something which is measured in degrees (0..360)
and would wrap round, so you could /not/ shift red without shifting blue
as well.

Cheers,
David

wrote in news::

> Photoshop's hue/saturation control will shift red to blue and leave blue
> where it is, for example.
>

Not in PS 6. If you make a blue fill, and bring image|adjust|hue &
saturation, and if you turn on "preview", you can slide the hue slider back
and forth and see every color of the rainbow.

That's the default behavior. If you change the option on the dialog to
"blues" instead of "master" then it will only change the blues, while
leaving everything else alone.

Bob

--
Delete the inverse SPAM to reply

In message <>,
"David J Taylor" <david-> wrote:

> wrote:
>> In message <>,
>> "David J Taylor" <david-> wrote:
>>
>>> I regard Hue adjustment as rotating things round a colour circle, and
>>> therefore as something which should be reversible. Depends on which
>>> program does the adjustment? My perception probably comes from too
>>> much involvement in colour TV!
>>
>> Photoshop's hue/saturation control will shift red to blue and leave
>> blue where it is, for example.
>
>Oh, in which case it's not operating how I would expect a hue control to
>operate. To me, hue is something which is measured in degrees (0..360)
>and would wrap round, so you could /not/ shift red without shifting blue
>as well.

Even if all tools worked as you thought, hue would still be in a
different class than color balance tools, as there is no way to go from
0,255,0 to 0,0,255 in any of them.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

In message <Xns95B6996B677CDbobatcarolnet@216.196.97.142>,
bob <> wrote:

>That's the default behavior. If you change the option on the dialog to
>"blues" instead of "master" then it will only change the blues, while
>leaving everything else alone.

That is what I was talking about.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><