LaserSoft Imaging

[norris_watkins]

These questions are w.r.t Silverfast SE Plus 8.0
Silverfast documentation movie says it is the 'overall brightness'
1. But how exactly is the midtone calculated.
Is it teh average brightness of the pixel ? ( Or is it teh mean brightness ? )
2. Also how is it calculated in the 'L' ( Logirithmic ) mode ?
( When I looked at the Gradation curve, I see that it changes differently depending on whether you select 'L' ( Logarithmic ) or 'N' ( Normal ). - so the calculation has to be different )
3. Also I see that in the histogram window, midtone value shown on the graph is different from teh midtone value shown numerically as shown in the picture. Why is this ?
4. Is there a way to see the input historgram in SF ?
( I see the histogram getting affacted when I make various changes - So it has to be the output histogram )

[LSI_Morales]

Hi norris,

The midtone is the point located in the middle between the brightest and the darkest point in your picture's histogram. If you move the midpoint it will affect the overall brightness.

Also how is it calculated in the 'L' ( Logirithmic ) mode ?
( When I looked at the Gradation curve, I see that it changes differently depending on whether you select 'L' ( Logarithmic ) or 'N' ( Normal ). - so the calculation has to be different )

The midpoint does not change between Logarithmic or normal views.

3. Also I see that in the histogram window, midtone value shown on the graph is different from teh midtone value shown numerically as shown in the picture. Why is this ?

I'm afraid I don't really get this question, would you please elaborate?

4. Is there a way to see the input historgram in SF ?
( I see the histogram getting affacted when I make various changes - So it has to be the output histogram )

Sure, the input histogram is the one you see in the "Histogram" tool, the output histogram is the one you see in the "Picture settings" panel

Cheers

[norris_watkins]

Thank you Morales. Few questions still remain :

The midtone is the point located in the middle between the brightest and the darkest point in your picture's histogram. If you move the midpoint it will affect the overall brightness.

1. Im not sure this is true. Im looking at the histogram now ( shadow=83, midtone=-9, highlight=254). If its the midpoint between brighttest and darkest points, then it should have been 168.5 ( 83+254)/2 = 168.5

2. What does it mean to change midtone to 'Logarithmic' ( by clicking the rectangle 'L' next to 'Midtone' in 'Picture Settings' )

3.

Sure, the input histogram is the one you see in the "Histogram" tool, the output histogram is the one you see in the "Picture settings" panel

But I dont have any histogram in 'Picture Settings'

[LSI_Morales]

Hi norris

First I will start by making a correction in my previous statement. I confused your previous question about the midtone with something else (sorry about that).

The midtone is a curve comprising the entire range of tones from the darkest point to the lightest point (without changing darkest and lightest points). These can be seen by opening the gradation curve and moving the midtone slider (either in gradation curves panel or in the picture settings pannel) or by moving the midtone slider in the histogram.

1. Im not sure this is true. Im looking at the histogram now ( shadow=83, midtone=-9, highlight=254). If its the midpoint between brighttest and darkest points, then it should have been 168.5 ( 83+254)/2 = 168.5

The scale of the midtone is independent from the rgb values of the histogram (0-255); it extends from -30 to +30 where 0 represents a straight line and -30 and + 30 the extremes (you can see this by moving this value while looking at the curve).

2. What does it mean to change midtone to 'Logarithmic' ( by clicking the rectangle 'L' next to 'Midtone' in 'Picture Settings' )

It changes from a normal curve to a logarithmic curve (again check the gradation curve to see the difference, most apparent at both extremes).

But I dont have any histogram in 'Picture Settings'

The output histogram is available only in SilverFast Ai Studio, it is part of the picture settings panel and looks like this:

Output Histogram.png (20.82 KiB) Viewed 190 times

Kind regards