Well the conversation went on for several posts and finally I invited posters to define what they consider a "blown out" image. IOW, how featureless must the image be to meet your criteria of "blown out." Thought it might explain why the disparity of opinions beyond the monitor's contribution.
Jack --- On Mon, 4/5/10, David Parsons <[email protected]> wrote: > From: David Parsons <[email protected]> > Subject: Re: Define "blown out" :-) > To: "Pentax-Discuss Mail List" <[email protected]> > Date: Monday, April 5, 2010, 1:07 PM > I didn't see a question in your first > post. > > On Mon, Apr 5, 2010 at 3:44 PM, Jack Davis <[email protected]> > wrote: > > I only read as far as about half of your first > sentence. I didn't need to read further as it was obvious > you had missed the point of the question. > > > > Jack > > > > --- On Mon, 4/5/10, Godfrey DiGiorgi <[email protected]> > wrote: > > > >> From: Godfrey DiGiorgi <[email protected]> > >> Subject: Re: Define "blown out" :-) > >> To: "Pentax-Discuss Mail List" <[email protected]> > >> Date: Monday, April 5, 2010, 12:05 PM > >> On Mon, Apr 5, 2010 at 10:27 AM, Jack > >> Davis <[email protected]> > >> wrote: > >> > I'll offer mine the nebulous term by saying > that if at > >> least some surface areas are rendered featureless > by virtue > >> of being too bright, I'd consider those areas > "blown out." > >> Many images can tolerate a certain amount of this > condition, > >> but it's amount is the criteria and varies with > each viewer. > >> Said areas must, of course, contain some available > mask > >> detail which defines the surface. > >> > IOW, I'm not talking about an absolute ball > of glare > >> wherein no detail is discernible. > >> > >> There's nothing nebulous about "blown out". > Consider areas > >> of pure > >> white with no detail as Zone 9 on the Zone System > >> scale defined as > >> follows: > >> > >> Zone 0 – key black or pure black – carbon or > photo > >> paper black. > >> Zone 1 – near black – shadows in faint light > or rooms > >> without light. > >> Zone 2 – dark gray/black – only subtle > textures are > >> visible. > >> Zone 3 – very dark gray – distinct shadow > texture is > >> visible. > >> Zone 4 – medium dark gray – slightly darker > “black” > >> skin, dark foliage > >> or shadows in landscapes. > >> Zone 5 – medium gray or 18% gray – darker > “white” > >> skin or lighter > >> “black skin,” light foliage or the dark blue > of a clear > >> blue sky. > >> Zone 6 – mid-tone gray – average “white” > skin or > >> shaded areas in snow > >> on a bright, sunlit day. > >> Zone 7 – light gray – pale “white” skin, a > concrete > >> walkway in sunlight. > >> Zone 8 – gray/white, near white – distinct > highlight > >> detail, like a > >> white wall in sunlight or brilliant surfaces in > flat > >> light. > >> Zone 9 – known as key white or pure white – > pure white > >> paper or snow > >> in bright sunlight. > >> > >> (Normally I think of the Zones as being from 1-10, > but > >> Ansel was a C > >> programmer and did a 0-based count ... ;-) > >> > >> So, by definition, anything you want detail in is > "blown > >> out" if your > >> exposure has placed it above Zone 8 on the above > scale. > >> > >> Since I've never seen any application use 16-bit > number > >> scales to > >> describe pixel values, you can determine what > areas of your > >> image are > >> "blown out" in Photoshop or Lightroom using either > a > >> percentage scale > >> or an 8-bit pixel value scale and floating the > cursor over > >> white-looking areas while looking at the > information > >> display panel. > >> Presuming that the exposure did not go to > saturation and > >> there is data > >> in those bright areas, you can place them in > adjustment > >> using the > >> Exposure (aka white point) sliders. This table > makes it > >> easy ... > >> > >> http://homepage.mac.com/godders/zone-system-numbers.jpg > >> > >> EG: you have a near blown out area in a photo that > you want > >> to ensure > >> images with detail on screen and in your prints. > Float the > >> cursor over > >> it in Lightroom and see that it is currently at > about 94% > >> in all > >> channels (or in one of them if that is the > significant > >> color of the > >> area). Nudge the Exposure slider in the negative > direction > >> until it is > >> in the range of about 85-88% to set that as the > brightest > >> point. Now > >> make adjustments with the mid-tone, black point > and Tone > >> Panel to > >> bring the rest of the photo into line with a > satisfactory > >> display. > >> > >> A certain amount of area at Zone 9 is fine, as > long as it's > >> not where > >> you wanted to convey detail. Too much Zone 9 in an > image > >> generally > >> looks bad. Another thing to be aware of is that > many papers > >> and > >> monitor screens cannot display the full 10 zone > scale very > >> well, or > >> have non-linear characteristics ... That's why > calibration, > >> profiling > >> and testing for DR are essential to good quality > image > >> display, > >> whether on screen or on paper. > >> -- > >> Godfrey > >> godfreydigiorgi.posterous.com > >> > >> -- > >> PDML Pentax-Discuss Mail List > >> [email protected] > >> http://pdml.net/mailman/listinfo/pdml_pdml.net > >> to UNSUBSCRIBE from the PDML, please visit the > link > >> directly above and follow the directions. > >> > > > > > > > > > > -- > > PDML Pentax-Discuss Mail List > > [email protected] > > http://pdml.net/mailman/listinfo/pdml_pdml.net > > to UNSUBSCRIBE from the PDML, please visit the link > directly above and follow the directions. > > > > -- > Aloha Photographer Photoblog > http://alohaphotog.blogspot.com/ > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link > directly above and follow the directions. > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
