A tool, I hope, for measuring mattes in Excel

[Ulophot]

Please see my newer post of this same title. Don' t use my attempts here.

Invariably, when I have to cut a matte, I am reminded that there are three kinds of people: those who can count, and those who can't. Even when I succeed in getting everything right the first time, it takes me forever, if only to anxiously triple-check myself before cutting yet another matte wrong by forgetting to include something in my calculation, or simply making a math error--my specialty--or converting fractions to decimals and back again.

I tried a centering rig a few times once and found it inadequate. I don't necessarily print to simple dimensions, e.g., to an even 1/4 inch, and rarely have to matte more than one copy of a given photograph.

It occurred to me last night that Excel might be able to make life easier. So, this morning, looked up a few things and created the attached file.

IF SOMEONE WHO IS COMPETENT AND WILLING TO CHECK MY WORK WOULD KINDLY DO SO, I WILL BE MOST GRATEFUL.

Anyone is free to use this. I have put in sample image measurements. By measuring to the nearest 16th-inch, no measurement is less or other than 1/32. That's more precision than needed, but rounding to a 16th might be a mistake, since it could go either way in either dimension.

In the Excel sheet:

Measurements are based on inches.

The sheet is set up now for horizontal mattes. Just switch the Matte Size dimensions for vertical. Or change them to 14 x 18 or what ever size you use.

"Image Float" is the white print border between the matte and the image edge. The sheet is set for 1/4 inch.

The "Remainder" column is somewhat superfluous but let's me use the cell for calculating the ones to the right.

I have two ways of calculating top and bottom borders: If I sign the matte, I give extra width to the bottom border. If I sign the print, I make the top and bottom equal, giving space for the signature in the bottom float area. I hope I got this right.

If this is actually functional, I'll add a section for 8 x 10 mattes as well.

See post below for for zip folder with Excel sheet.

[Erik Larsen]

Hi Philip, here’s a pretty simple calculator for cutting mats of any size with a visual aid. I find it takes the math headache away!
https://www.russellcottrell.com/photo/centering.htm

[Drew Wiley]

All the big boys now do it with computerized mat cutting machines. But most of them are getting too lazy to use unequal mat borders, even though it is just a punch button operation for them. My lower margins are always wider for esthetic reasons; but I never use any fixed rote formula for that - it all depends on the specific image. Same with the edge differential between the trimmed print itself and the window mat cutout. It has to look and feel right for each image, whether on a little 5x7 inch print or a big one nearly four feet wide.

I once had an early version of an Esterly Speed cutter, which allows all four borders to be set at once. It only worked for 2-ply back then. But their later machines were much more heavily built, and I wish I could justify what is now probably around a 4K price tag. But I can't, and still use my old 1K linear Logan.

Frankly, working in metric is a lot easier than in inch fractions. But I do both, and have everything from tape rules to precision calipers with both kinds of readings.

[Doremus Scudder]

All my prints are different dimensions and aspect ratios. However, I use a few standard mat sizes (digression: I think "mat" is for mat board and "matte" for the non-reflective surface, right?). I've standardized on 14x18, 16x20 and 22x28, with the occasional 20x24 or 16x24 (this latter for panorama formats).

When I go about positioning a print on the board, I use a centering T-square that I cobbled together myself. It consists of a regular, good-quality T-square that has inch (and/or mm) scales at least on the long arm. I then cut and glued a metal rule on the left arm of the T, positioning it so that the scale reads from 0 at the intersection of the right-hand edge of the long arm and increases in value from left to right.

Use is as follows:
1. Position trimmed print with its right side flush against the right side of the mat board. Position the T-square with the T against the left side of the mat board and laying over the print. Measure and note the distance from the left side of the mat board to the left edge of the print.

2. Now position the T-square at the top left of the mat board. Use the horizontal rule to align the left edge of the mat board with the position on the scale that corresponds to half the measurement you took in step one. E.g., if step one yielded 12 1/2 inches, you'd position the half-scale rule so the 6-1/4-inch mark was aligned with the left edge of the mat board. This is the proper position to center the print horizontally. I weight my T-square at this point with a shot bag; it should not move any more.

3. Now, position the print against the long side of the T-square and flush with the bottom of the mat board. Note the measurement from the top of the mat board to the top of the print. Divide this in half and position the print with its top edge aligned with that mark; e.g., if the top of the mat board to top of print measurement is 7-3/4, you'd position the top left corner of the print at the 3-7/8-inch mark.* This centers the print vertically.

*Note: If dividing fractions by 2 is not your thing, then simply get a fine-point permanent marker and make half-scale markings on your rule, or get a thin half-scale rule and add it to the rule that's there.

4. Now add whatever bottom weighting you like. If you use a formula, just use it to figure how much to move the print up. I use my eye; some images like a lot of breathing room at the bottom, others feel good with just a little. However you do things, position the print by moving it up along the long edge of the T-square to the appropriate position and then weight it with a shot bag.

Your print is now well-positioned on the board. Still, I'll check measurements with another long metal rule or tape measure to make sure the side borders are equal and that things are parallel top and bottom. My Rotatrim trimmer is really accurate, but occasionally there's a print that's a tiny bit out of square (usually by 1/32 or less of an inch, but sometimes a bit larger). In that case I have to decide how to compromise the position.

I reposition, if needed, by carefully moving the print with the weight still on it. I'm pretty good at moving it in really small increments. I'll tweak and measure till I get it right. 95% of my prints need no repositioning. At this point, tack down the print and put it in the dry-mount press (or whatever you do to adhere it to the mount board).

As for cutting windows: I to like a "float" around my prints as well. Smaller prints get 1/4 inch top and sides and 3/8 inch on the bottom. Larger prints get 3/8 inch and 1/2 inch respectively.

To cut the windows, I simply measure from the sides and top of the board to the edges of the image and subtract the right amount (1/4 or 3/8 inch) from that measurement and pencil it in lightly on the back of the mat board. Same for the bottom, only I subtract the larger amount (I leave a bit more room at the bottom for my signature).

Sometimes subtracting 1/4 or 3/8 inch from another measurement can be tricky, especially if you have a measurement that has 32nd-inch increments in it. I get by by simply converting to the smallest denominator, e.g., 3/8 inch = 6/16 = 12/32. So, for example, if I have to subtract 3/8 from 3-5/32, I first convert 3-5/32 to 2-37/32 (borrowing 32/32 from the 3) and subtract 12/32 from that; 37-12=25, so 2-25/32-inch is my result. If you don't need to be precise to the 1/32-inch, then using the 1/16-inch increments is even easier. Having a chart handy with all the conversions may be helpful if you're not the best at subtracting unlike fractions.

Then it's just a matter of being careful applying those measurements to the mat cutter. Some expert mat cutters just use two measurements, cut those and then eyeball the other cuts. I can't that well, so I use the stops on my mat cutter for all cuts.

Best,

Doremus

[Ulophot]

I'm familiar with the optical print centering. I tried it and wasn't always pleased.

I appreciate the examination of each image on the board, though I find this cumbersome sometimes in my circumstances. If I stand on a chair to get far enough away, light or reflections or other distractions cause problems; vertical positioning is exasperating. An 8x10 is one thing to play positioning with; larger becomes a problem for me.

Doremus, you flatter me with math skills that I don't have. You're writing to someone who cannot put two pieces of wood together without making a mistake. Someday I'll tell you about trying to custom fit a plywood table top to an irregular corner with a hot water pipe passing floor to ceiling. My Excel idea is to leave the calculations to a "machine" instead of spending half an hour on each mat just on calculation and then making a mistake anyway. If I matted every week, maybe I'd get it down, but it's more like every several months, and all it takes is one little slip-up.

Anyway, as mentioned above, I tried the centering rig and gave it up. I spent hours trying to figure out how to add precision scales, but then the numbers were right back in my face. Can you imagine how many times I have mistaken 5/8s on a ruler for 3/8s? I should have been professional waltzer -- you only have to count to three.

[Ulophot]

Drew, as I thought about it last night, it occurred to me that, having entered the image dimensions in Excel and gotten results, I can try placing the print on the mat to see if it would be better slightly up or down. If so, I can measure either top or bottom and change the number in Excel.

Of course, given the caveats of using "eye-balling" that I indicated above, it may not always work for me, but it might for others. And it's still not the finely tuned process you use.

Anyway, having realized that I can put the Excel file in a zip folder and attach it, here it is.

Mat Measurements.zip

[Doremus Scudder]

Philip,

I took a look at your Excel sheet; it seems a good tool.

Still, it seems to me, that you are going to have to measure both the print and the board (more later) as well as measuring to position the print.

Measuring the print itself accurately is going to require that you use a good metal rule and align the print edge not with the edge of the rule, which is the "0" mark, but rather somewhere else, like the 1-inch mark, to get a really accurate measurement. That means subtracting that 1 inch from the final measurement.

Measuring the board is a really good idea. I won't tell you the whole story about how a frame shop I had cutting windows in 22x28" board ruined several because the board was actually 22 1/8 x 28 1/16... I just got a few pre-cut 16x20 mats that were all 1/8" bigger along the long side. The point being, you can't just assume the YxZ-size board you just bought is really that size. I ended up trimming the 1/8-inch extra on a bunch of boards simply because I was using them as window mats on boards that were exactly 16x20 and I didn't want the overlap.

Once you have those measurements (and haven't made any mistakes by confusing 5/16 with 7/16 or whatever) and have transferred them correctly to your Excel spreadsheet and come up with your measurements, you still have to measure to position and square the print on the board. That means two measurements along at least two sides to get both proper position and square. Then you'll want to check the other sides to make sure they agree, just in case there has been some dimensional changes in the board or paper due to changes in humidity, temperature, mistakes, whatever.

My point being: you're still going to be doing a lot of measuring There are only a couple of things I can think of the make that process easier. First, get a good rule and a good tape measure (check that they agree!) with easy-to-read markings. Ones with markings at 1/8-inch increments are available. The second is to convert to metric, since that eliminates dealing with the fractions; millimeters are way close enough for mounting purposes. The only catch there is that your mat board is going to be a weird size in metric: 11" = 279.4mm, 14"=355.6mm, 16"=406.4mm, 20"=508mm, etc.

All that will work fine, but your method ends up with a minimum of eight separate measurement per print plus checks. Mine has three measurements only, two of which, however, need to be divided in half, plus a final positioning and then checks. The downside is that there doesn't seem to be a centering T-square with properly positioned scales and with reliefs the right thickness for 4-ply mat board. Like I said, I cobbled mine together, which entailed adding a precision metal rule with a reverse scale (half of a centering ruler) and then shimming the long arm with a piece of aluminum as well as filing down the relief on the crosspiece so that it lay completely flat on the mat board when in use.

So, use whatever method works best, but you might reconsider the centering T-square idea later if you find that all that measuring is introducing too much error.

You should know that I ruin a mat board every now and then by forgetting to subtract the float when cutting the window mat, or transferring the measurements to the mat cutter incorrectly. Still, I'm way ahead on costs doing things myself.

Best,

Doremus

[Ulophot]

Doremus, I had to start laughing as I read your latest. There must be some aria that parallels this, or perhaps some comic plot. Laughter is a great way to surmount one's challenges. A wise old friend of mine once said, "If you can't laugh, you can't think."

So. I have not one but four steel rulers, of three lengths, one of which has agate and picas marked in addition to mm and inches, and which is the only one that uses, not the end but a flat "hook -- it's a printer's rule -- as the O-point; the other three start indented about an eighth-inch. My 30-inch T-square also has inches marked, but somewhat roughly.

I am aware of the vicissitudes of mat board measurements. I also know that frame interior measurements are not always accurate I learned the hard way. Why lead a boring life? The good news is that I was able, finally, about a year ago, to buy a Logan mat cutter (Compact Elite), a major improvement after decades of using my art school Dexter.

As to the 8,351 measurements, my process, which seems to work as long as I don't botch the overmat window, is a little different. I drymount my prints to 2-ply Bristol first, then mount in a 4-ply sandwich: Having cut the window mat, I hinge it and, leaving it open, place the print on the back, roughly positioning it, and lower the window. Ensuring that the window mat stays square with the back, sometimes with a small, felt-lined clamp at one corner, I then position the print to align it to the window. That's the tricky, and sometimes frustrating, part, but it eliminates numbers. Once done, I put a weight bag on the print, open the top, and mark the corners lightly in pencil on the back board. Then I use the linen hinging tape to mount print on the back and double-check window alignment.

[Michael Rosenberg]

Doremus
Can you contribute a photo of you mat jig? It sounds better than the jig I use.
I use the same mat board dimensions btw.
Mike

[Tin Can]

I took a Print Maker college level he wanted only

Hand Torn edges thick paper

Alt printers are way fussy