Orpington Astronomical Society

Astronomy => Technical => Topic started by: JohnP on Jan 23, 2009, 15:39:07

Title: Photoshop Question....
Post by: JohnP on Jan 23, 2009, 15:39:07
I tend to do all my post processing in Photoshop. I will spend ages 'perfecting a black & white 16-bit raw so it looks as best as it can on the monitor. I then change mode to 8bits & save as high resolution jpeg. Whenever I open image in another program such as windows file viewer or explorer etc. the jpeg image always looks a lot darker than my image in photoshop so all the subtle nebula details are lost.

Have I got something set wrong in pshop (maybe processing in wrong mode etc.)

This does my head in as the only solution is to go back into photoshop & make the image look a lot brighter before I subsequently save in jpeg mode....

Any help, please..... :-)

John
Title: Re: Photoshop Question....
Post by: Mac on Jan 23, 2009, 17:07:14
The problem is that you are saving it as a black and white picture.
If you've done all your processing in 16bit greyscale and are then changing it to 8 bit and saving it,

change the mode to RGB, first and then change it to 8 bit,
when you save it as a jpeg, make sure the ISS Profile, adobe rgb is ticked,
you should then get the same image in picture viewer as you have in photoshop.
Title: Re: Photoshop Question....
Post by: JohnP on Jan 23, 2009, 17:17:23
Mac - What can I say except cheers mate.... it works... Not sure where to check where ISS adobe profile is ticked but I did everything else & it works...

Thks a lot - I owe you a beer for that one - it's been doing my head in trying to figure out what was wrong -


John
Title: Re: Photoshop Question....
Post by: Mac on Jan 23, 2009, 17:35:07
Quotemake sure the ISS Profile, adobe rgb is ticked,

when you click "save as" and select the jpg option, you should have the ISS profile option as a tick box,

This should also make it easier if you print the photos as they are in the RGB colour space.
Title: Re: Photoshop Question....
Post by: RobertM on Jan 23, 2009, 18:09:13
I owe you a beer too Mac, I've been scratching my head about that for a while now !
Title: Re: Photoshop Question....
Post by: JohnP on Jan 23, 2009, 18:23:11
Robert - glad to know I am not the only one - you don't know how much it's been peeing me off.. The 'cheat' I used has been to increase the grey (middle) slider on the levels by about 20% before saving & I was always concerned this was doing something to rest of image but at least brightness seemed to be about right. Mac's method works a treat & sounds correct... :-)

Mac - Thks again - Sounds like we need to organize a session with all the beers you are owed plus of course we still need to 'wet the babies' head :-)

John
Title: Re: Photoshop Question....
Post by: Fay on Jan 23, 2009, 18:32:43
Mac, I have ICC profile , is it that one?
Title: Re: Photoshop Question....
Post by: Mac on Jan 23, 2009, 21:46:52
after selecting save as:

(http://www.macrhon.co.uk/website/oasphotos/fay/saveas.gif)

and selecting .jpg as the file type, you should be presented with the following screen

(http://www.macrhon.co.uk/website/oasphotos/fay/RGB.gif)

Just make sure the ICC RGB Profile is ticked.

That way the image should stay the same, when you open it in other viewers.
also if you are prining the images, most printers will recgonise the Adobe RGB profile and you should get the same image in print.


Title: Re: Photoshop Question....
Post by: Carole on Jan 23, 2009, 22:54:47
How can I save this whole thread for future easy reference?

Carole
Title: Re: Photoshop Question....
Post by: Mac on Jan 24, 2009, 05:07:43
QuoteHow can I save this whole thread for future easy reference?

one easy way is to add this thread to your favorites.

If you click on the links from the main forums page.

Orpington Astronomical Society > Astronomy > Technical > Photoshop question.

the address bar in internet explorer will have the full and correct address for this post, which is (below)

http://forum.orpington-astronomy.org.uk/index.php?topic=4226.0 (http://forum.orpington-astronomy.org.uk/index.php?topic=4226.0)

all you then do is to goto the top of internet explorer click on favorites and then add favorite,
then you will have a permanent link to this thread.
it might be worth while creating a new folder called forum tips, and creating it in there, that way everything is in one place. :lol:

Mac.
Title: Re: Photoshop Question....
Post by: doug on Jan 24, 2009, 09:41:41

     That`s clever!!!!!   How on earth do you manage to copy a window from your computer onto the Forum.  I would be interested to know for showing windows to other people, without having to describe them in words.  Doug.
Title: Re: Photoshop Question....
Post by: JohnP on Jan 24, 2009, 09:50:01
Doug,

All you do is hit the print Screen button (PrtSc) on your keyboard. This copies whatever is currently on your screen to the clipboard. You can then go to an editing program (you could also you word) & do a Ctrl-V or Edit Paste. You then need to save the file as something & upload it to the forum as normal....

John... :-)
Title: Re: Photoshop Question....
Post by: Mac on Jan 24, 2009, 11:39:17
Doug, I use the method exactly as described by John.

In photoshop, after you've pressed print screen,
press Ctrl + n
to get a new image, the size will be exactly the same size as your print screen!
crop the image down to what you want the person to see,
then instead of save or save as, use save for web.

change the numbers of colours to 128, and then select either 128 dithered or no dither,
as its only a screen shot you are sending, the image file size is normally tiny.

(http://www.macrhon.co.uk/website/oasphotos/fay/doug.gif)
Title: Re: Photoshop Question....
Post by: Carole on Jan 24, 2009, 13:32:55
Brilliant, thanks Mac, didn't think of that.

Carole