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Student using HDR first time - image very red, ok after update ONCE, then red again

Sep 6, 2012 3:20 PM

I hate to ask in a room full of pros, but here we go. Using WIN7 64 bit

Purchased CS6 and takiing first class. CS6 ver 13.0.1 64 bit.

We are learning about HDR. We have been provided 3 dng images of a model (a young lady) to work with.

I have done the same thing four times and the opening image is darker with a lot of red.

 

File_Automate_Merge to HDR Pro

I select the tree images (they all look nice)

Make sure the "Attempt to Automatically Align Source Images box is checked"

Click OK

PS makes layers, one being a merge to HDR pro layer

 

Arrgghhh. I just installed the update (I was using 13.0 64 bit) just before posting this and was going through the motions as I typed in here and...... the image opened perfectly and I was able to do the lesson. However, I tried to do it  a second time, just to make sure...it is very red again. Any help please?

 
Replies
  • Currently Being Moderated
    Sep 6, 2012 9:06 PM   in reply to garetoo
     
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    Sep 6, 2012 9:25 PM   in reply to garetoo

    When vewing the hdr image in photoshop what mode are you in? Image>Mode>8, 16, or 32 bits/channel

     

    Which mode you choose will make a difference in how it looks on the screen.

     
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    Sep 6, 2012 10:47 PM   in reply to garetoo

    Your monitor is only capable of displaying 8 bits/channel, so its up to you to decide on what can be thrown out when viewed. When photoshop is in 16 or 32 bit/channel, it is doing the deciding for you and can cause issues. When you switch to 8 bits, you should get a window that asks you what to do with the data.

    I am starting to get to my limit of knowledge on the subject. so hopefully someone else will chime in soon and confirm or deny my limited knowledge.

     
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    Sep 7, 2012 9:20 PM   in reply to garetoo

    Your video cards display is usually 16, 24 or 32 bits total. The settings used in photoshop are for each channel.

     

    There are 3 channels for the monitor Red, Green and Blue. Each having 8 bits or 8+8+8= 24 bits or 16777216 colors as there are 256 color per channel and 256 3rd power is 16,777,216.

     

    So a 32 bit video card would be 256 to the 4th power.

     

    Now back to photoshop, 16 bits per channel is 512 colors per channel or 512 to the 3rd power or 134,217,728 colors

     

    Therefore 32 bits per channel would have 1024 colors per channel or a total of 1,073,741,824.

     

    Keep in mind for this example I only used the RGB channels, photoshop is capable of creating multiple channels, granted these extra channels are primarily used for tansparency, masks, and selections. But in theory one day these extra channels could be used to display extra color information on the screen along with the main RGB channels.

    To prove this, just switch to CMYK, that mode is displaying 4 channels instead of 3 on the screen. So who's to say that one day someone will create a new color mode that all monitors will adopt as a standard? Photoshop is ready and waiting, most of the coding is already done.

    Anyway I am getting off subject a bit, so I better stop...

     
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    Sep 7, 2012 11:40 PM   in reply to Silkrooster

    Silk - you're still confusing bits per channels with bits total (which really shouldn't be used, it's misleading)

     

    8 bits per channel == 24 bits total in RGB == 16 million possible colors

    16 bits per channel == 48 bits total inRGB == a lot of colors

    32 bits per channel == 96 bits total in RGB == more colors than you can count easily

     
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    Sep 8, 2012 1:47 AM   in reply to Chris Cox

    No not really, you said the same as I did, I just left out the total for 16 and 32 as I figured he got the idea from the 8 bit example.

    I was showing him, the difference between the settings on the video card and what photoshop uses and why they are different.

     
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    Sep 8, 2012 5:40 AM   in reply to Silkrooster
     
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    Sep 8, 2012 12:43 PM   in reply to Silkrooster

    >> Now back to photoshop, 16 bits per channel is 512 colors per channel or 512 to the 3rd power or 134,217,728 colors

     

    Nope.

     

    16 bits/channel is 32769 values per channel in Photoshop, or 32769^3 possible colors.

     

    32 bits/channel is sort of 4 billion values per channel (not simple since it's floating point), or 2^96 possible colors.  In layman's terms that's a metric $%^-tonne of possible colors.

     
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  • Noel Carboni
    23,523 posts
    Dec 23, 2006
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    Sep 8, 2012 7:49 PM   in reply to Chris Cox

    Chris Cox wrote:

     


    16 bits/channel is 32769 values per channel in Photoshop, or 32769^3 possible colors.

     

    That number is 35,187,593,412,609 (35 trillion and change, almost as much as a Wall Street executive's bonus ).

     

     

    32 bits/channel is sort of 4 billion values per channel (not simple since it's floating point), or 2^96 possible colors.

     

    79,228,162,514,264,337,593,543,950,336

     

    If I remember my 5th grade math correctly, that's 79 octillion colors.  Forget about metric $%^-tonnes, that's something like a million times as many colors as there are stars in the observable universe.

     

    -Noel

     
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    Sep 8, 2012 8:29 PM   in reply to Chris Cox

    Ok, you caught me. Thats what i get for not double checking my figures. Never the less you stregthened my point, in that there is no way a monitor can display all of the colors that 16 and 32 bit provide. Maybe one day, just not yet.

     
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