Mechanical Pitch Test

[Giovanni Remigi]

As you may know, the mechanical pitch is required when you want to interlace multiple images on the same lenticular sheet. The optical pitch is not enough and we need the mechanical pitch too.

A common way to measure the mechanical pitch is to print a pattern of vertical lines, place the reversed lens on the top of it and use a loupe to find the pattern having all vertical lines appearing exactly under every single lens. I find this technique very difficult.

I probably found an easier way to measure the mechanical pitch (the actual size of the lens) and I would like to get some feedback from you.

We start by printing a normal color optical pitch test and place the lens on the top of it as we usually do.

Instead of looking from the expected viewing distance and find the bar with the most uniform color, we instead look very close to the print through a narrow hollow cylinder.

We move our cylinder from left to right and we look for the color that moves at the same speed as our cylinder.

This bar gives the mechanical pitch. What do you think? From my simulated tests, this technique seems to give very precise values without using a loop.

Regards,

Giovanni

[Harvey Floyd Photography]

How very interesting. I will have to try this. 

~Harvey

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[Giovanni Remigi]

Highlighted in red is the extra panel that likely will be available in Lentigram Professional. It seems that the only extra parameter required to interlace multiple images on the same panel is the Mechanical Pitch.

Regards,

Giovanni

[Harvey Floyd Photography]

Cool. I’m not 100% sure I follow the pitch test viewed with a cylinder but I think I do. 

How narrow does it need to be? How tall? Does it need to touch the print? Would a lens help or hurt? I’m thinking of a jewlers loop which is more narrow than my standard printer’s loop. Or a jewelers loop without the lens in it maybe? It would be cool to set a loop like this op on a guide rail that you could pass a print under, one line at a time to find the mechanical pitch. 

Cheers,

Harvey

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[Giovanni Remigi]

The main idea of the cylinder is to force your eye look at the lenticular sheet perpendicularly, to limit your side vision. You need to find the color that moves at the same speed as your eye, but if you look at an angle it wouldn't work. For very small sheets it could be a loupe, for bigger ones it could be a thin glass.

If you use a loupe you should look for the bar which keeps the same color while you slide the loupe horizontally across it.

I'm planning to add a classic mechanical pitch test to Lentigram anyway. You can see the icon already next to the one for the pitch test in the previous screenshot. I just find the classic mechanical pitch hard to align but it could still give you better precision.

Giovanni

[Parallax Printing]

This is very exciting and represents a pretty big new addition to the software side of things. It will be cool for laminated lenticular prints but finding mechanical pitch is a requirement for flatbed printing.

The biggest change I would like to see as you move forward with a new version of the software is an update to the registration system. It works as it is but a few things would make it considerably more robust, saying this from experience of using 3DMK (with custom settings) in comparison.

1) expand the colors in the registration to 6. Having CwMwYw gives you a much greater registration resolution and allows you to see more clearly optical inconsistencies in the lens. Its easier to dial things in with precision when you have 6 colors.

2) make the color registration go around the entire perimeter. Its useful to have it on full top and bottom and not just on the sides.

3) change the way the alignment system works. I know you probably don't want to copy 3DMK but their alignment system for determining center is so clean and easy to use it makes precision work simple. 

Just my $.02 :)

Chris

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Chris Dean  |  2615 Wolcott St. Suite D Ferndale MI 48220  |  248-397-5156