Pages: [1]   Go Down

Author Topic: Artwork Copy & Flat-Field Correction - Lightroom.  (Read 796 times)

William Walker

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1101
    • William Walker Landscapes
Artwork Copy & Flat-Field Correction - Lightroom.
« on: October 17, 2021, 05:32:09 am »

I would be happy for someone to tell me why this is not a good idea.... :)

I understand that Flat-Field Correction is there to profile/correct light falloff in older lenses...

I also know that getting even lighting for artwork copy can be tricky for those of us who do not have professional studios, easels and lighting...

I did a "rough & ready" test yesterday and would love to hear your thoughts on this idea...

I set up my tripod in an area that I know is not evenly lit and followed the Flat-Field Correction procedure described here:- https://youtu.be/G7oaLJhXRGs.

I asked someone to just hold a picture and this is what I came up with.

The first two images, "Original" and "Internet 2" were taken as per the instructions and "Internet 3" is the final result  - all without any adjustments.

The final result appears to be very evenly lit...

I look forward to your comments.
Many thanks
William
Logged
"What can be asserted without evidence can also be dismissed without evidence." Christopher Hitchens

petermfiore

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 2666
    • Peter Fiore Fine Art
Re: Artwork Copy & Flat-Field Correction - Lightroom.
« Reply #1 on: October 17, 2021, 08:06:42 am »

Why is the art in plastic wrap when you are photographing? Glare and distortion are abundant.


Peter

William Walker

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1101
    • William Walker Landscapes
Re: Artwork Copy & Flat-Field Correction - Lightroom.
« Reply #2 on: October 17, 2021, 08:44:05 am »

Why is the art in plastic wrap when you are photographing? Glare and distortion are abundant.


Peter

Hi Peter, as I said, "rough & ready" - the objective here was not to do a proper copy of the artwork - it was merely used as a prop to see if the lighting was "evened out" - which it seems it was.

Obviously, when doing the job properly I would use an easel too, not someone holding the artwork. Pay more attention to the white background to check the evenesss of the lighting.

Again, the exercise was to see if the Flat-Field Correction in Lightroom could be used to even out the lighting without affecting the artwork.
« Last Edit: October 17, 2021, 08:50:59 am by William Walker »
Logged
"What can be asserted without evidence can also be dismissed without evidence." Christopher Hitchens

petermfiore

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 2666
    • Peter Fiore Fine Art
Re: Artwork Copy & Flat-Field Correction - Lightroom.
« Reply #3 on: October 17, 2021, 11:41:46 am »

I do this all the time, photographing my paintings. I understand the need to work out the lighting in terms of glare, white balance, and even distribution.

Stephen G

  • Full Member
  • ***
  • Offline Offline
  • Posts: 171
Re: Artwork Copy & Flat-Field Correction - Lightroom.
« Reply #4 on: October 18, 2021, 10:27:28 am »

Yes, the Flat Field correction thingy in Lightroom does work, but you can't turn off its colour correction aspect (lens colour cast correction? I can't remember). I found that for flat field correction it does not work as well as Equalight, which I trust and have used almost daily for ten years.
Logged

Slobodan Blagojevic

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 17899
  • When everyone thinks the same, nobody thinks
    • My website
Re: Artwork Copy & Flat-Field Correction - Lightroom.
« Reply #5 on: October 18, 2021, 12:36:37 pm »

... I understand that Flat-Field Correction is there to profile/correct light falloff in older lenses...

You kids have to ruin everything with your new lingo  ;)

For the rest of us, "flat-field" is a property of a lens, mostly macro, to render center and edges more or less equally sharp. Normal (curved-field) lenses are unable to provide the same precise focus in the center and at the edges.

imagetone

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 97
    • http://www.tonymayimages.com
Re: Artwork Copy & Flat-Field Correction - Lightroom.
« Reply #6 on: November 01, 2021, 05:29:36 pm »

Iím a bit puzzled by your procedure.

You would normally substitute a uniform white surface for the artwork in the subject plane to get your correction frame. Then you are in effect correcting for uneven lighting plus any vignetting in your chosen lens/aperture. I use the equivalent tool in Capture One to correct any residual unevenness in lighting when I copy artwork after trying to light as evenly as possible first.

Are you saying you used your ďOriginalĒ frame as the basis for the correction? Iím not familiar with the tool in Lightroom but am surprised it can cope with the horizontal lines of the siding and hasnít attempted to correct those out. Or did you put up some white seamless paper/board?

The other problem you will have if you are using natural light for copying artwork is that as well as having to alter exposure and check white balance every time the light changes, you should also shoot a new correction frame too.
Logged
Pages: [1]   Go Up