Wednesday, February 02, 2011

scanner vs photograph Part 1 using a scanner - the difficulty of copying coloured pencils in moleskine sketchbook and some solutions

stage 3: Final image using scanner with adjustments in Photoshop

I've been comparing scans and photographs of this little sketch of evening fields in coloured pencil in a moleskine sketchbook.

I find coloured pencil can be difficult to reproduce. Scanners or cameras can pick up the top layers of colour too strongly (And I scumble lots of layers). With cream coloured paper they make it too white, using the cream for their white balance and that makes the whole image cooler.

There may be better ways but this is the way I try to solve it:

With the Scanner
  • scan image into Photoshop or similar programme - I don't like to make the adjustments in the scanner if it isn't quite right, as photoshop has more options so I usually accept the scan as it is

  • in Photoshop duplicate the layer

  • look at options for the opacity of this layer - this one needed 100% opacity but this is variable. This intensifies the colours without distorting them and doesn't usually darken the pale colours overmuch.

  • Flatten the layers.

  • Look at Levels to see if any tweaking needs doing there

  • Now go to the colour balance, I adjusted the lights to add a lot of yellow and a little magenta to get closer to the creamy colour of the moleskine page and add the warmth back to the paler areas of the sky. It's now pretty close to the original.

Below you can see it at stage 2 with the layers duplicated and flattened but the levels and colour balance not yet done.

stage 2

Stage 2: It's too cold and white, losing the creaminess of the moleskine paper and the pale apricots in the evening sky - there in the original but not showing up.

stage 1: the original scan

Original scan: All too pale, too cool, missing the paler colours in the sky that are there in the original sketch.


Tomorrow I'll show the photograph and see which gave the best result.

I hope this is helpful.

4 comments:

nielsp said...

As I am also a photographer I do understand the problem with capturing your images digitally and having them display as you originally saw them.

The first problem we have is that no matter what lightning we are using (tungsten, incandescent , florescent or other) our eyes will always convert any white tint created with high-lighting to pure white.

Our camera tries to do this and this is why we ave light settings or cloudy, sunny, etc to compensate.
The other problem most people have is that they take their images in Jpeg, which set the White Balance (WB) at capture and for many cameras it also tends to make the colours more vivid.
I always recommend to use camera RAW if available or pick the best camera WB settings.
The scanner is an identical device as the digital camera except in a different case and different focusing abilities.

The scanner will for the most part perform better. With pastels if it is not all fixed will leave residue on the scanner glass.
Most plain white papers actually has a blue tint (optical brighteners) so using that in the image to set WB will produce warmer image (blue shifted to red end).

If you want better WB then use a photographic grey card at side of image and use this to set WB and crop for effect.

Also most people ahve the screen set way too bright (blue) changing your screen to a Wb of about 6,000k will produce images that seem more normal.
Please feel free to contact me with any camera or editing question.

Niels Henriksen

My Camera World
Niels Henriksen Artworks

vivien said...

Thank you Niels for a great explanation :>)

I clearly need to get to grips with the white balance AND learn to shoot RAW - my 'big' camera can do this and I've never actually used it yet

I do scan pastels sometimes - and yes it always involves cleaning the glass :>) - now they tend to scan beautifully.

Sarah Wimperis said...

interesting post viv! I often wonder which is best, obviously for small pieces, how do you deal with the distortion that photos give, bending the straight lines etc?

vivien said...

Hi Sarah

with small images I use the macro setting and wide angle and then the lines aren't distorted

- with bigger images I try to use telephoto and sacrifice a 'border' area of backgroun (cropped out) to minimise any distortion. Corel has a good tool for making sides parallel again if you took it at a slight angle by mistake, that I find useful (prefer photoshop generally though).

I'm no genius at this but these seem to work for me. Any further input from Niels would be welcome :>)