OK, let me substitute 'not quite white' instead of grey. Imagine what is probably the most frequent use case of blown out areas in clouds. Rather than losing all detail my thoughts are that it might be best to do something like map (255,255,255) to white but say (255,254,243) to some averaged value such as (254,254,254). That would avoid colour casts but still avoid throwing away such highlight detail as remains in the unblown channels. I think it would look better than a large expanse of pure white.
But retaining colour information would be better provided it doesn't cause colour casts. Raw Therapee have put a lot of work into this but even there you still you get colour casts, sometimes. Whenever we invent data with some interpolation algorithm there is always going to be the odd example that throws it. I haven't worked on a blown colour casted highlight reconstruction recently, but it strikes me that we can perhaps deal with such colour casts more easily in dt than any of the other raw converters. Let's say our reconstruction causes a typical magenta colour cast in the reconstructed areas around totally blown highlights - I suspect we could just use our parametric masks to run a magenta subtracting colour change just on the brightest pixels and if necessary add a drawn mask as well. -----Original Message----- From: Chris Siebenmann [mailto:c...@cs.toronto.edu] Sent: 07 June 2013 15:13 To: Rob Z. Smith Cc: darktable-users; c...@cs.toronto.edu Subject: Re: [Darktable-users] Best way to recover highlights that are blown in processing? | On 13-06-06 10:14 AM, Chris Siebenmann wrote: | > I would be happy to see a highlights reconstruction option for 'if | > any channel is clipped, set the pixel to white'. I might even turn | > it on all the time. [...] | | It might be nicer if such an option set the pixel to grey rather than | white using the values of the remaining unblown channels to take a | best guess at how near to full white that grey should be. My thinking on this is that white splotches on pictures look less ugly than grey splotches. To some extent we are trained (especially now) to expect very bright areas in pictures to be white; I'm not sure that very bright areas looking grey instead will look at all pleasent. I wouldn't be surprised if they came out looking rather wrong. - cks The content of this email is private and confidential, and unless otherwise stated only the intended recipient may use the content of this email for its intended purpose. If you are not the intended recipient, you may not retain, copy, forward or disclose the information herein, and we ask you to notify the sender or contact our Customer Services department on 0844 633 1000 or at cssupp...@nhbc.co.uk The copyright and all other intellectual property rights subsisting in or to the contents of this email belong to NHBC or are used with the permission of the owner and all such rights are reserved. Recipients are asked to note that opinions, conclusions and other information in the contents of this email that do not relate to the official business of NHBC are neither given nor endorsed by NHBC. This email has been scanned for viruses, but NHBC does not accept any liability in respect of loss or damage caused by any virus which is not detected by its virus detection systems. Data Protecti on Act 1998. NHBC is the Data Controller for the purposes of the Act. Your personal details will be stored and processed in accordance with the Act for the purposes of dealing with your enquiry or claim and for research and statistical purposes. If you make a claim under a Buildmark policy you agree to your data being passed to others involved with your claim such as the original builder, or a consultant or remedial works contractor that we may employ in connection with your claim(s) and matter ancillary to your claim(s). Other than disclosure provided for in this statement, we will not pass any data about you to any other party without your permission unless we are required to do so by law. NHBC, the National House-Building Council, is a company registered by guarantee in England, registration number 320784, and it is authorised and regulated by the Financial Services Authority. ------------------------------------------------------------------------------ How ServiceNow helps IT people transform IT departments: 1. A cloud service to automate IT design, transition and operations 2. Dashboards that offer high-level views of enterprise services 3. A single system of record for all IT processes http://p.sf.net/sfu/servicenow-d2d-j _______________________________________________ Darktable-users mailing list Darktable-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/darktable-users
