Re: [Gimp-user] Whitening Background

[Richard <strata_ranger hotmail com>]

> Date: Sun, 6 Mar 2016 06:54:17 +0100
> From: forums gimpusers com
> To: gimp-user-list gnome org
> CC: notifications gimpusers com
> Subject: [Gimp-user] Whitening Background
>
> I am a beginner to Gimp and I hope this is a very easy question to answer.  
>
> I took a photo with my phone of a simple Blank & White label.  I opened it in
> Gimp and saved it as a .PNG file.  What I need to do is brighten or whiten the
> label background.  When the picture is printed the White comes out greyish.  I
> need to whiten this greyish background so when I print the label it comes out
> White.
>
> I've tried everything I've learned in Gimp the past year but I simply cannot
> figure this out.  Any/All help would be greatfully appreciated.
>
> Thank you!

This is actually a common, even expected, procedure to perform any time you're cleaning up an image taken 
from a scanner or camera.  When you're initially taking the image, look around for any 
brightness/contrast/exposure related settings and use them because if you can get it right before capturing 
the image this will improve the quality of the end result even if you still need to make further adjustments 
to it in GIMP.  Similarly, if your device has a highlight/shadows "alarm" function then switch that on to 
highlight any areas that are over/underexposed and washed out as either black or white.  Normally washout is 
bad for a photograph, but in this case you're printing a label and you WANT the white areas of the source 
material to be washed out so the printer won't attempt to shade them in.

In GIMP's case, go to the Colors menu and pick either the "Levels" or "Curves" command -- the next steps vary 
depending on which tool you prefer but in either case you need to take the Highlight setting and brighten it 
until your white background tone washes out (becoming a solid RGB white).

- For the Levels tool, Highlight is shown directly in the dialog and corresponds to the arrow mark at the 
white end of the spectrum.  Click and drag this mark to the left (into the light-gray area of the spectrum) 
to brighten the image.
- For the Curves tool, Highlight is the node at the top-right corner of the graph.  Drag it to the left 
(keeping it aligned along the top edge) to brighten the image.


-- Stratadrake
strata_ranger hotmail com
--------------------
Numbers may not lie, but neither do they tell the whole truth.