...I'm sorry, your english is slightly hard to follow.
How embarrassing... :-(
sorry, let me ask again so simple as i can:
You wrote: "There are no dots", but i see yellow dots in your first picture and orange in the second picture...
You wrote: Customer wanted to fill in the
"white" areas of the
screened PMS with yellow.
I understand: In your file and on the plate there are items (grafic elements), they are coloured with 50% tone of spotcolour orange (PMS 1505).
A nearby perfect print will reach about 63% (up to 4% more or less) on the coated paper caused by the increase printed with an 175lpi screen (a 200 lpi screen can cause a higher increase than a 175lpi, if not perfectly calibrated, i´m sure you know that...).
The other 50% in the file and on the plate (and ideal 37% "paperwhite" in the 175lpi print) should be filled up with yellow
?
(Not with overprinting the same element in 100% Yellow,
but the negative, white 37% "dots"?)
I could not believe that and that´s the reason for asking.
But if that should in fact be the aim, i think you have to consider, that in file and on plate 50% screen yellow already as bitmapped 50% screened dots causes also an increase of about 13% up to 20%. That causes naturally overlapping and it only works via bitmaps in the file, otherwise there are big problems with the angles for PMS and Yellow...
Next possible horror-feature in this context could be trapping the bitmaps in a wrong direction (not the right way increasing yellow to overlap orange (PMS 1505), but the other direction: Orange (PMS 1505) increased to lay under or over yellow...)
I want to apologize my inquiry, i really do not suspect your knowledge and you harvested already very good inspiration from others here and i guess they are nearer by the truth as my thoughts:
One looks at first to the ink and the other to the press, i myself (as a prepress-worker) looking for possible faults on my side first and my intention is just to make you really sure, that your view to the topics is correct ;-)
Should i really write you a german version? I would like to do that, but i also hope that is not neccessary ;-)
Sollen wirklich die "negativen" papierweissen Raster-Punkte in der jeweiligen 50% gerasterten orangen Pantonefarbfläche in Gelb gedruckt werden und das Gelb soll nicht Pantone Orange überdrucken?
Best wishes
Ulrich