Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
10-08-2019, 05:17 PM   #16
Senior Member

Join Date: Apr 2015
Location: Western Washington
Posts: 204
Original Poster
Today I taped the canvas to a wall in a room with a window with Venetian blinds. The blinds were on the north wall with the canvas on the east wall. The camera was mounted on a tripod and the pictures were shot with a downward angle with the blinds in the closed position. This resulted is the best results, the combination of side lighting plus the downward angle as well as the muted lighting worked out well. The outside lighting varied from full sunny to cloudy. The pictures with the sun shining produced the best results. It's amazing how much can be recovered from the raw files in Photoshop! This technique did require distortion correction.

The goal of this project is to replace the face on the canvas with that of a friend. This is well beyond my current Photoshop skills. My brother talked me into this project. I will have to somehow match the friends face as close as practical and then paste it in. The lighting effect on the canvas is different from that of the glossy photograph of the friend. The result will be printed on canvas. I will be spending quite some time on Youtube "educating" my self on how to pull this off.

10-10-2019, 04:57 PM   #17
Loyal Site Supporter
Loyal Site Supporter

Join Date: Dec 2017
Photos: Gallery | Albums
Posts: 1,093
As hinted at earlier in this thread, polarizers will work, in principle. The flashes or other sources would be filtered by polarizers oriented in the same direction (up/down, say) while the camera polarizer is set 90 degrees relative (right/left, say). Because of the way digital cameras perform metering, the camera polarizer should be of the "circular" polarizer type. Crossed polarizers work because specular reflections retain polarization, while diffuse reflections become depolarized. Note that at shallow angles, the reflectivity of nominally diffuse targets becomes ever more specular in the plane of the source-eye line of sight, so the light sources should be relatively normal to the plane of the object, but not so straight on as to be imaged by the camera if the target were a mirror. Expect a factor of 4 effective reduction of detected diffuse light relative to use of no polarizers. Specular light reduction will depend on the quality of the polarizers, which may not be spectrally uniform.

While it may be possible to use large diffuse light sources to obtain an adequate representation of the target details and colors, in principle any specularity that the target or its protective covering has will cause the addition of a haze to the image that is the color temperature of the light source(s) if the light sources are in a position from which they can specularly bounce off of the target and into the camera. (As a gedanken experiment, imagine a 25% reflective silvered mirror covering the target. The image of the target would be a combination of the reduced light from the target and a semi-transparent mirror view of any lighting within the reflected camera field of view, hence even taking the photo inside a giant white integrating sphere -- a perfectly diffuse world of light -- would not avoid the appearance of haze. Fortunately, AR glass coverings and an ink printed target surface itself have relatively low specular reflectivity and in the real world this haze may be too slight to be a distraction except perhaps at the blackest end of a gray scale test pattern.) I would think that shiny oil paintings with irregular surface angles would be most affected by this if lighting positioning is not carefully thought out.

  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
art, camera, canvas, exposure, flash, frame, galleries, glass, light, lighting, photo studio, position, post, print, prints, reflections, source, strobist, uniform, viewer
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
K5 with 5Mb File JPG how large can I print on Canvas FreeSpirit9 Troubleshooting and Beginner Help 15 03-19-2017 04:02 AM
Panoramic Canvas Print Shop Recommendation? LFLee Digital Processing, Software, and Printing 7 11-27-2012 01:17 PM
Will this shot print at A2 canvas? joshfishkins Troubleshooting and Beginner Help 22 11-02-2012 02:43 AM
Canvas print not exact to image on screen pete_pf Digital Processing, Software, and Printing 2 04-22-2012 04:19 PM
Questions about Canvas print YJD Photographic Technique 4 09-30-2009 06:33 AM

All times are GMT -7. The time now is 03:27 AM. | See also:, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]