Color QC and Matching Blog

Color Correction – How to use your color software to get practical answers

Posted by Elaine Becker on Thu, Jul 16, 2009
Have you experienced a case where the color computer wants to double the batch size and add a ton of white to correct a batch?  Or maybe it's adding some red and you think the color is already too red? A common complaint about color matching software is that it gives bad answers or impractical adds to correct the color of a batch. 

Well...this frequently happens when a minor colorant is overshot in the batch and the only way the computer knows to correct it is to dilute it out by adding all of the other colorants.  Remember, the color computer is always trying to go for the perfect match or DE=0.00.  Often times this is not the "perfect answer" in the practical world.  The colorist is frequently able to accept a small color difference if he can fix the batch with the add of one colorant, or a small add of two colorants.    In these cases, using the manual correction features of OnColor can solve the problem by giving you control with practical choices on how to adjust the color of a batch.

The Manual Add feature gives the colorist complete freedom to "fix" the batch with whatever colorants and amounts he chooses.  The colorist usually starts by setting the computer generated adds to zero for all amounts.  Looking at the color plot and  color differences, the colorist can then try different adds and see the effect on the delta components and the DE.  Using his knowledge of the colorants and products, he can interface his practical experience to get an answer that gets him to an acceptable tolerance, while still being a reasonable add.  Colorists like this feature because it puts them in control of the decision making process.

The Optimize Add feature is used to try and correct the batch with an add of only one or sometimes two colorants.  In many cases, a colorist will prefer correcting a batch by only adding one colorant.  This is due to speed and simplicity.   The Optimize Add feature allows him to select the colorant and then automatically computes the "best add" (the add that will yield the lowest DE) of this colorant.  If needed, he has the option to optimize on another colorant if it is needed to get within tolerance.  The benefit of this feature is that the batch may be adjusted to an acceptable DE with a small add of only one or sometimes two colorants.  The fewer colorants to be added, the less chance there is of making a mistake or mis-weighing a colorant.

The Reduce Add feature uses a special algorithm to reduce the size of the add by accepting a DE greater than 0.0.  The user inputs the DE or tolerance that he can accept, and then the color matching software computes the smallest add that will get within this tolerance.

Using these manual adjustment routines can greatly speed the batch adjustment process.  They save time and money by making smaller adds than the automatic add, while allowing the operator to blend his practical experience with the sophisticated algorithms of the color computer.

Tags: Color correction, color matching