Best Combination of Film and Developer for Sharpness?

[RalphLambrecht]

... To find out about this I consulted 3 or 4 general photographic books and wikipedia as well, that all explained resolution and the measurement of it with b/w line patterns and said that is indicated in lines per mm or line pairs per mm, but none of them explained, what lines per mm do exactly mean and that it is the same with lp/mm. ...

You are not consulting the right books!

Sorry, couldn't resist.

 

[A49]

Ok, I surrender. It was a fault to concentrate too much on German books. The times of J.M.Eder, when really important photographic books were published in German language seem to be over. I will add your WBM book to my library order. After having read it, I probably can give up using this part of the forum for asking.

Best,
Andreas

 

[dpgoldenberg]

Let's assume you've drawn five 0.1mm thick lines, 0.1 mm apart from each other. The result is a frequency (or resolution) of 5 line pairs per mm (lp/mm). If you only count the black lines, you get 5 lines per mm (lines/mm), and if you count black and white lines, you get a resolution of 10 lines/mm.

Some researchers would report the above as 5 lp/mm, some as 5 lines/mm, and some as 5 cycles/mm. I've never seen it reported as 10 lines/mm.

I think that some of the confusion on this topic comes from those pesky digital people! When considering the maximum resolution for a digital sensor, it takes a minimum of two pixels to record a line pair (or cycle). So, if you have a sensor that segment that is, say, 10 pixels long, the maximum that segment can resolve is 5 cycles. Thus, the "resolution" typically cited for a digital sensor can be thought of as "lines" per unit length, but has to be divided by two in order for it to be expressed in terms comparable to the resolution measured in the way discussed here.

David

 

[Q.G.]

I think that some of the confusion on this topic comes from those pesky digital people! When considering the maximum resolution for a digital sensor, it takes a minimum of two pixels to record a line pair (or cycle). So, if you have a sensor that segment that is, say, 10 pixels long, the maximum that segment can resolve is 5 cycles. Thus, the "resolution" typically cited for a digital sensor can be thought of as "lines" per unit length, but has to be divided by two in order for it to be expressed in terms comparable to the resolution measured in the way discussed here.

David

i don't know. I have never heard or seen that the resolution of a digital sensor is expressed in lp/mm.
Pixels (total number of), yes. Pixels per mm too. If anything, always exagerating the count by ignoring Bayer patterns.

Resolution, resolving power, is the maximum number of lines per unit a system can render. Not cycles, or pairs of lines.
You can express that either as lines per mm (which is the direct measure) or as line pairs per mm (lp/mm) (in which case the number is halved - the halved numbers in this thread being represented as lines per mm was what made me jump in).

I'm sure the confusion stems from people writing "lpmm" instead of "lp/mm" and assuming the "p" stands for "per" (which is why the "/" is dropped too).

 

[RalphLambrecht]

... You can express that either as lines per mm (which is the direct measure) or as line pairs per mm (lp/mm) (in which case the number is halved - the halved numbers in this thread being represented as lines per mm was what made me jump in).

I'm sure the confusion stems from people writing "lpmm" instead of "lp/mm" and assuming the "p" stands for "per" (which is why the "/" is dropped too).

My experience is that some folks have difficulty accepting the imaginary 'white' lines between the actual black lines as lines at all, or (for similar reasons) they have difficulty with the concept of line pairs and cycles. Consequently, some researchers call the resolution out as (black)lines/mm, in which case, the resolution is identical to lp/mm.