Acceptable Dot Gain Window

[jason]

I don't know where this guy figures his math, but I am not even with that.

Check his website out, I doubt he has the math wrong.

If a digital dot WITHOUT a curve in it reads 50%, then you are reading it at 60% of the Press sheet to make it easier... that is 20% dot gain. The 50% dot is PHYSICALLY 20% larger than it originally was.

Your making it too complicated, it's just face value. Trust me.

[David]

most people use the word "points" when referring to dot gain, like "my 50 reads a 70, so I have a 20 point dot gain"...

most people don't try to calculate the actual percentage.
If you are in fact getting a 70 read on your 50, you will probably see plugging in the shadows, most presses today will yield less than that, like in the 12-15 point gain, we here, on a bad day, can get almost 11 points gain, but we run a pretty tight press room.

[Aaron]

No plugging. We're running 20m Staccato. Looks pretty good actually.

[DigitalCrapShoveler]

Yes I agree David. Points NOT percentages. And, Jason.... I am not arguing if the guy is wrong, or I am wrong, or even you are wrong... I am simply stating Percentage-wise the math is wrong. Point-wise it IS correct. AM I making any sense... I haven't had nearly enough coffee.

[jason]

If you are in fact getting a 70 read on your 50, you will probably see plugging in the shadows, most presses today will yield less than that, like in the 12-15 point gain

A lot of the larger printers around where I am are switching over to GRACOL. According to the GRACOL 2007 specs the TVI or Dot Gain for Grade #1 & #2 paper is Y=18%, M=20%, C=20%, K=22%.

If you are running GRACOL, then your Black will read as 72% on the press sheet. You will not see plugging in the Shadows if you monitor your Print Contrast which GRACOL says should be at 40.

Anyone notice that GRACOL & Pantone Color Bridge have roughly the same print specs??

[jason]

I am simply stating Percentage-wise the math is wrong. Point-wise it IS correct.

David explained it quite well, when talking dot gain it is referred to as Points.

Screw coffee, how about a beer.

[DigitalCrapShoveler]

I am simply stating Percentage-wise the math is wrong. Point-wise it IS correct.

David explained it quite well, when talking dot gain it is referred to as Points.

Screw coffee, how about a beer.

Hell yeah! I'll mix it with my coffee and Heroin for the day! Hahahahahaha, yeah, glad Dave got it there. Helps when we are all on the same page. :laugh:

[G_Town]

I've heard it explained both ways but personally I've always did it as Jason explained it.

[DigitalCrapShoveler]

Me Jason, or Jason-Jason? Hahahahahahaha! Don't answer that G_Toner... DCS makey jokey.

[David]

I've also used both ways, because it's not 20% of the 50% dot, it's 20% of the 100.

50% plus 20% (of the 50%) = 60
whereas 50% plus 20% (of the whole 0-100) = 70%



now, go running down the hall and scream cause your head is gonna 'splode Lucy!

[David]

here's the math:

Note that, unless Δ0,50 = 0, either the highlight critical printing fraction, awf, will be non-zero, or the shadow critical printing fraction, avf will be not unity, depending on the sign of Δ0,50. In instances in which both critical printing fractions are non-trivial, Viggiano recommended that a cascade of two (or possibly more) applications of the dot gain model be applied.

 

[DigitalCrapShoveler]

Yeah... thanks?

[G_Town]

DCS, kill him.

[DigitalCrapShoveler]

Oh wait... you mean Dave!?!

[G_Town]

Oh that's fine just so long as someone pays for that blatant use of math.

There's no math in prepress :angry: