LAB colour mode to fix underexposed photos?

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Tue, 11 October 2005 11:28 Go to next message
Synapse Syndrome (Advanced Photoshop user)
I had a tutorial printed out from the web, from about 7 years ago, which was
a lengthy one showing how you could make a seriously underexposed photo look
much better using Lab Colour mode. The tutorial was dedicated to some guy
that had just died, and the photo involved in the tutorial featured him
making his last presentation. The photo was downloadable, so that you could
do the tutorial.

Does anybody, by any chance remember this tutorial?

If not does anybody know any similar ones? I got some underexposed photos
that I need to make usable as soon as possible.

Cheers

ss.
Tue, 11 October 2005 12:56 Go to previous messageGo to next message
BCHELLER65 (Photoshop begginer)
This method doesn't use the Lab color mode, but it almost always
produces at least satisfactory results:
Open the file in Photoshop as usual. Duplicate the layer and change
the blending mode for the second layer to "Overlay". If still too
dark, duplicate the second layer using Overlay mode. At some point,
the image will look too light. This can be controlled by manipulating
the transparency of one of the duplicate layers.
Tue, 11 October 2005 13:08 Go to previous messageGo to next message
Synapse Syndrome (Advanced Photoshop user)
<BCHELLER65@HOTMAIL.COM> wrote in message
news:1129049795.285227.4590@g14g2000cwa.googlegroups.com...
> This method doesn't use the Lab color mode, but it almost always
> produces at least satisfactory results:
> Open the file in Photoshop as usual. Duplicate the layer and change
> the blending mode for the second layer to "Overlay". If still too
> dark, duplicate the second layer using Overlay mode. At some point,
> the image will look too light. This can be controlled by manipulating
> the transparency of one of the duplicate layers.
>

Cheers, I have tried this, and it works pretty well on a photo that is
generally underexposed, but it makes things worse on photos with
underexposed backlit subjects. Maybe masking is needed?

Hmmn. Well, I need to get a 4 or 5 of these badly done photos fixed as well
as I can, as they are very good, apart from the backlighting that screwed up
the camera's auto-exposure.

ss.
Tue, 11 October 2005 15:18 Go to previous messageGo to next message
Mike Russell (Photoshop expert)
"Synapse Syndrome" <synapse@NOSPAMgomez404.elitemail.org> wrote in message
news:diglmh$io$1@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com...
>
> I had a tutorial printed out from the web, from about 7 years ago, which
> was a lengthy one showing how you could make a seriously underexposed
> photo look much better using Lab Colour mode. The tutorial was dedicated
> to some guy that had just died, and the photo involved in the tutorial
> featured him making his last presentation. The photo was downloadable, so
> that you could do the tutorial.
>
> Does anybody, by any chance remember this tutorial?

It's a Dan Margulis article, and the guy was Tom McMillan. AFAIK it is no
longer online. Two different procedures are described in his last two
editions of Professional Photoshop.

> If not does anybody know any similar ones? I got some underexposed photos
> that I need to make usable as soon as possible.

DM's more recent procedure involves several steps. One was to assign a
false profile that used Wide Gamut RGB's primaries, and with a gamma of
..75. More than likely the blue channel will need help; it's generally the
first of the three to turn into noise. To deal with this, blend in either
the red or green channel. Then use Lab to adjust contrast as needed, and
(because of the intense primaries of wgRGB)tone down the colors by reducing
the slope of the a and b curves.

In general, I find that RGB does a better job at dealing with slightly
underexposed images. This is because color, brightness, and contrast are
lacking in such images, and RGB will increase all of these at once. This
may also be done in Lab mode, but I usually find it harder to get as good a
result.
--
Mike Russell
www.curvemeister.com
Tue, 11 October 2005 14:52 Go to previous messageGo to next message
saswss (Advanced Photoshop user)
In article <digriq$feh$1@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com>,
"Synapse Syndrome" <synapse@NOSPAMgomez404.elitemail.org> writes:
> Cheers, I have tried this, and it works pretty well on a photo that is
> generally underexposed, but it makes things worse on photos with
> underexposed backlit subjects. Maybe masking is needed?

In CS or CS2: Image>Adjustments>Shadows&Highlights


--

Warren S. Sarle SAS Institute Inc. The opinions expressed here
saswss@unx.sas.com SAS Campus Drive are mine and not necessarily
(919) 677-8000 Cary, NC 27513, USA those of SAS Institute.
Tue, 11 October 2005 15:49 Go to previous messageGo to next message
Synapse Syndrome (Advanced Photoshop user)
"Mike Russell" <RE-MOVEmike@Curvemeister.comRE-MOVE> wrote in message
news:JdU2f.567$D13.81@newssvr11.news.prodigy.com...
> "Synapse Syndrome" <synapse@NOSPAMgomez404.elitemail.org> wrote in message
> news:diglmh$io$1@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com...
>>
>> I had a tutorial printed out from the web, from about 7 years ago, which
>> was a lengthy one showing how you could make a seriously underexposed
>> photo look much better using Lab Colour mode. The tutorial was dedicated
>> to some guy that had just died, and the photo involved in the tutorial
>> featured him making his last presentation. The photo was downloadable,
>> so that you could do the tutorial.
>>
>> Does anybody, by any chance remember this tutorial?
>
> It's a Dan Margulis article, and the guy was Tom McMillan. AFAIK it is no
> longer online. Two different procedures are described in his last two
> editions of Professional Photoshop.
>
>> If not does anybody know any similar ones? I got some underexposed
>> photos that I need to make usable as soon as possible.
>
> DM's more recent procedure involves several steps. One was to assign a
> false profile that used Wide Gamut RGB's primaries, and with a gamma of
> .75. More than likely the blue channel will need help; it's generally the
> first of the three to turn into noise. To deal with this, blend in either
> the red or green channel. Then use Lab to adjust contrast as needed, and
> (because of the intense primaries of wgRGB)tone down the colors by
> reducing the slope of the a and b curves.
>
> In general, I find that RGB does a better job at dealing with slightly
> underexposed images. This is because color, brightness, and contrast are
> lacking in such images, and RGB will increase all of these at once. This
> may also be done in Lab mode, but I usually find it harder to get as good
> a result.


Hi Mike, thanks for your reply.

Yes, the procedure you describe rings a bell. I don't have the book you
mention. Do you know of any links that could help me fix these pics?

The ironic thing is that these are old snaps of a very close friend of mine
who tragically drowned last week in Thailand. I want to get these done so I
can send them to our other old university friends before the funeral.

ss.
Tue, 11 October 2005 19:51 Go to previous messageGo to next message
Mike Russell (Photoshop expert)
From: "Synapse Syndrome" <synapse@NOSPAMgomez404.elitemail.org>
[re fixing underexposed images]

> Yes, the procedure you describe rings a bell. I don't have the book you
> mention. Do you know of any links that could help me fix these pics?

Here's one that uses curves only:
http://www.curvemeister.com/tutorials/misfortunate/index.htm

> The ironic thing is that these are old snaps of a very close friend of
> mine who tragically drowned last week in Thailand. I want to get these
> done so I can send them to our other old university friends before the
> funeral.

I'm sorry to hear this. Email me one of the files and I'll see if I can
come up
with a procedure. With your permission I'd like to use it as material for
this month's class. I can assure you that the image will not be distributed
outside of the class.

Mike
Thu, 13 October 2005 12:36 Go to previous message
Synapse Syndrome (Advanced Photoshop user)
"Mike Russell" <RE-MOVEmike@Curvemeister.comRE-MOVE> wrote in message
news:2eY2f.538$tV6.391@newssvr27.news.prodigy.net...
> From: "Synapse Syndrome" <synapse@NOSPAMgomez404.elitemail.org>
> [re fixing underexposed images]
>
>> Yes, the procedure you describe rings a bell. I don't have the book you
>> mention. Do you know of any links that could help me fix these pics?
>
> Here's one that uses curves only:
> http://www.curvemeister.com/tutorials/misfortunate/index.htm
>
>> The ironic thing is that these are old snaps of a very close friend of
>> mine who tragically drowned last week in Thailand. I want to get these
>> done so I can send them to our other old university friends before the
>> funeral.
>
> I'm sorry to hear this. Email me one of the files and I'll see if I can
> come up
> with a procedure. With your permission I'd like to use it as material for
> this month's class. I can assure you that the image will not be
> distributed
> outside of the class.
>


Thanks, email sent

ss.
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