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Colours From 21 Step Wedge Look Strange To Me

Re: Colours From 21 Step Wedge Look Strange To Me

2017-02-21 by brian_downunda@...

The best way to check is to measure it and look at the a & b values.

Some papers are warmer than others, so there is a subjective element here.

I find the neutral QTR curves on an OEM 3880 to be warmer than neutral in practice, whereas ABW is cooler. It appears to me that QTR neutral doesn't add enough of the toning inks to neutralise the naturally warm black inks, whereas ABW adds too much.

If I want a more neutral print then as a quick and dirty method I print with around 85% "neutral" and 15% cool. Percentages are paper-specific require a little trial and error, although if you also measure the cool curve you can use the two sets of a & b values to make an educated guess.

Re: Colours From 21 Step Wedge Look Strange To Me

2017-02-21 by ian@...

Hello Brian

Can you tell anything from the LAB values

L* a* b* 94.769523 -0.762756 1.728522 91.256101 -0.203137 2.426518 87.45355 0.358367 3.219209 82.733287 0.98201 3.696157 77.814396 1.531754 4.07091 73.69646 2.017101 4.294673 69.170411 2.229375 4.162587 64.98 2.272277 3.718938 61.048939 2.299934 3.561152 57.40068 2.058672 3.321924 53.827364 1.898121 2.837888 50.63376 1.565484 2.500536 47.183377 1.147048 1.835083 43.653643 1.001303 1.58205 38.967692 0.820198 1.544497 34.99938 0.856993 1.813594 31.022183 0.82908 2.025414 26.076259 0.861397 2.001437 24.797505 0.904512 1.825907 21.442101 1.164079 2.080707 17.622641 1.490708 2.165402

Re: Colours From 21 Step Wedge Look Strange To Me

2017-02-21 by brian_downunda@...

I am not an expert in a & b values, but I can tell it's not neutral. From Wikipedia: "a*, negative values indicate green while positive values indicate magenta; b*, negative values indicate blue and positive values indicate yellow". Those numbers are some way from zero. In my limited experimentation with this you'd want values under 1. Previous post of mine still applies.


---In QuadtoneRIP@yahoogroups.com, <ian@...> wrote :

Hello Brian

Can you tell anything from the LAB values

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