RetouchPRO

Go Back   RetouchPRO > Technique > Photo Retouching
Register Blogs FAQ Site Nav Search Today's Posts Mark Forums Read


Photo Retouching "Improving" photos, post-production, correction, etc.

Posterization & tonal range from 10 -240

Reply
 
Thread Tools
  #1  
Old 06-10-2008, 06:18 AM
Dewcal Dewcal is offline
Junior Member
 
Join Date: Oct 2007
Location: Barnard Castle, UK
Posts: 23
Posterization & tonal range from 10 -240

Hi,

Am new to this forum and have joined as I am trying to come to grips with (some of) what CS3 can offer! I currently have two queries that I would appreciate help and direction on. Both of these result from sending some images (tif, 16bit) for publication and getting them rejected.

(FWIW, am using PC, with colour profiled monitor, shooting Nikon RAW, processed in ACR.)

Firstly, one image was said to show posterization. Is there a way of seeing this within Photoshop? I am failing to see the effect being mentioned with my eyes and yes, it could be because I am not sure what I am looking for!

Secondly, one image was knocked back as it had a tonal range from 3 to 250 and they are asking for a range of 10 - 240. Is this as simple (assuming initial good exposure) as setting clipping in Curves | Options to Shadows clipping 0.04% and Highlights 0.06% ?

Or should this be done via Levels and setting the Output levels to 10 and 240 respectively?

What is difference between these two methods? if they both do the "same thing" should one be preferred over the other?

TIA for any help you can give.
Dave
Reply With Quote top
  #2  
Old 06-10-2008, 02:25 PM
crazyfly1's Avatar
crazyfly1 crazyfly1 is offline
Senior Member
 
Join Date: Jan 2007
Location: Colorado Springs Co. USA
Posts: 733
Re: Posterization & tonal range from 10 -240

Hi Dewcal, welcome.
I don't have an answer to your first question, except to say that if you are saving in lossless TIFF format then that should not cause a problem. You may want to check your color settings and make sure you're in rgb and not pro rgb. You might also check for out of gamut warnings before sending off.

For your second question (me no good at math but I'll try). The curves dialouge does indeed let you intentionally set settings in the options to clip for just that purpose. However, the settings are in percentages of the whole so I'm thinking your safe at 1.0 and 1.5. Surely someone that didn't sleep through math will come along and give exact numbers for you. Keep in mind those settings only come into play when you click auto and that will apply some other adjustments as well.
Alternatly you can manually set the 10 and 240 you suggest for each image.
Yes levels and curves do what they do in exactly to same way, they just look different. Your idea of 10 and 240 with levels will work fine. Most professionals I think, prefer curves for the extra control it offers.

Last edited by crazyfly1; 06-10-2008 at 02:33 PM.
Reply With Quote top
  #3  
Old 06-10-2008, 03:17 PM
smak smak is offline
Senior Member
 
Join Date: Jan 2007
Location: Gainesville, Florida
Posts: 284
Re: Posterization & tonal range from 10 -240

The histogram can show posterization - where gaps and spikes are in the levels. Can look in RGB or individual channels.
Reply With Quote top
  #4  
Old 06-10-2008, 04:01 PM
Dewcal Dewcal is offline
Junior Member
 
Join Date: Oct 2007
Location: Barnard Castle, UK
Posts: 23
Re: Posterization & tonal range from 10 -240

Crazyfly1 & Smak,

Many thanks for your prompt responses - it begins to make sense! I will find a calculator and see what I can do in converting tones to % and inputting into curves to save a custom setting for this purpose.

Normally convert from ACR in ProPhoto and then change to Adobe or sRGB depending on use of file.

Will convert image again and look at histogram.

Thanks again.
Dave
Reply With Quote top
  #5  
Old 06-10-2008, 04:42 PM
smak smak is offline
Senior Member
 
Join Date: Jan 2007
Location: Gainesville, Florida
Posts: 284
Re: Posterization & tonal range from 10 -240

>>>>>>> it had a tonal range from 3 to 250 and they are asking for a range of 10 - 240.

If you are going to set H and S in Levels or in Curves by using the eyedroppers, first double-click on white eyedropper and set to 240 and 2-click on black dropper and set to 10.
Reply With Quote top
  #6  
Old 06-11-2008, 01:44 AM
Dewcal Dewcal is offline
Junior Member
 
Join Date: Oct 2007
Location: Barnard Castle, UK
Posts: 23
Re: Posterization & tonal range from 10 -240

Thanks smak - another short cut I did not know!
Reply With Quote top
Reply

  RetouchPRO > Technique > Photo Retouching


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Posterizing, Posterization thoughts and ideas Doug Nelson Photo-Based Art 11 09-11-2009 12:23 PM
Tutorial on dynamic range skydog HDR, Panoramas and Tone Mapping 2 12-02-2007 05:53 PM
HDR - ( High Dynamic Range ) Images CJ Swartz HDR, Panoramas and Tone Mapping 6 11-12-2007 03:40 PM
Tonal Range Help Dave_D Image Help 5 12-18-2005 11:06 AM
hi all. partly over exposed photo exorcist Image Help 6 12-28-2002 04:04 AM


All times are GMT -6. The time now is 04:03 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.
SEO by vBSEO ©2011, Crawlability, Inc.
Copyright © 2016 Doug Nelson. All Rights Reserved