Problem Calculate the size of image enlarged or downsized ?

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echavez123

echavez123

MGF, Master Grumble Framer
Joined
Jan 24, 2008
Posts
838
Loc
Las Vegas, NV
A customer comes in with a photo and wants to have it made larger or sometimes smaller. However, they want the enlargement to be 5x7 or 8x10 or some other standard size -- thinking they can put this into a cheap frame, right! The problem I have is, if the original photo is a given size, how can I tell if it will expand to the target size without having to crop part of the image? And if I have to crop it, where would the crop marks be on the enlarged image?

This is important because if the cropping removes part of a person's head or body part, it may not look good. The customer needs to be told this up front and I may need to try another size, or simply tell them it wont work in that size.

I have a couple of ways of calculating this, but both are a bit awkward:

1) create a blank image size of the original in Photoshop and resize - this tells me the dimensions. This is time consuming.

2) do the algebra using proportions, for ex: if the image is 4x6 and they want to enlarge to 8x10, the equation is: 4/6 = 8/x, solve for x. The answer is X=12. So the enlargement w/o cropping is 8x12, which means I need to crop 2 inches from the longer side to get an 8x10 image. I have to do this on a scratch sheet of paper.

There must be an easier way? Any ideas?

ernesto
 
I've found several web sites that provide "proportions calculators", but this is the one I ended up using:

http://www.algebrahelp.com/calculators/equation/proportions/

If you happen to handy with spreadsheets & formulas, you could easily make a spreadsheet for this.

Since I often use fractions & the proportions calculator works with decimals & I don't readily recall what .375 is as a fraction, I made a simple chart showing fractions <--> decimals for all fractions from 1/16 to 15/16. Easier to look at the chart than to take out the calculator.
 
What is so difficult about method #2? Easy equation.

Just cross multiply and it is simple math.

4/6 = 8/x

Therefore 4x=48

x=48/4

x=12
 
The ratio of a 35mm image is 2:3. None of the standard sized RM frames except 4x6 & 24x36 are sized to this ratio. The more common RM sizes (8x10, 16x20) are proportioned to a medium format camera negative (4x5).
 
If people are at the design counter and you need a quick appraisal of what is going to work, you and they won’t want to wait until you’ve gone to the computer, opened a spreadsheet and plugged in numbers.

I use your second method quite often. It’s reasonably quick and the customer sees that you’ve given it some thought and are not simply guessing.
 
If you practice it will be as easy as telling how much change from $100.00's to give them when the bill is $97.83. You can all do this quickly right?
 
Rob... I still have my proportion wheel in the store and it always seems to impress my customers.

Mine is over 20 years old.

Everyone who works with printing needs to have one of these in their shop.
 
Reproduction/proportion wheel is our friend! I still have mine from college...somewhere...I think I've seen one around the shop as well.

Without one, I figure out the factor: enlarge an 8x10 to something like an 11 x 14 would be a factor of 1 3/8, so an 8 x 10 would be an 11 x 13.75, for example. Divide 11 by 8, then multiply the factor by 10 to get 13.75. It's not perfect, but it's good for a pinch.
 
I do it in my head because I print everyday but the easiest way is to open it in a photo editing software while the customer is in the store. I have found that by opening it I eliminate phone calls and the need for the customer to come back in to make the decision. If it is also being framed I also try to print it right then so it can be designed from the actual print and when they return it is for pick up only.
 
I like opening it up in PS also. That way THEY can tell me what they want to get rid of in the photo.
 
I like Cavalier's simple method. What you are doing is calculating the aspect ratio.
The same method works in reverse if the proportions of the new print are more important to them than those of the original. This will tell them how much they have to decide to lop off.
:cool: Rick
 
I think Kodak used to make a sliding cropping tool where it would expand out or in to any proportion scale. It's like two "L" shapes sliding opposite each other. You can probably make one for your front counter and show the customer in proportion what would be cut off. If it was a digital file only, then photoshop would be the way to go. I also have that proportion scale and have used it for many years, it works great..
It's made by the
C-Thru ruler co out of Connecticut
1-800-243-0303
You can buy one at any printers supply store Item #PS79
Francisco
 
PicturedFramer said:
It's like two "L" shapes sliding opposite each other. You can probably make one for your front counter and show the customer in proportion what would be cut off.
Click to expand...

Gee that sounds like a mat that is cut in two.

If you knew of someone who has a discarded mat or two, or three... you could cut it up, mark it in inches and have a small, medium and large cropping guide.

This is one that we use.

Doug
 

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Of course this is all assuming that they even understand what a proportion is. I run into this all the time. I will often print out an 8x10 at 8x12 and then ask them what they want cut off. They then say nothing but I want it 8x10. Once I squeezed it to an 8x10 because no matter what I said, he didn't get it. Those were some mighty tall and thin people in that photo.
 
I was thinking that's what it might come to for some people. Might be a good way to achieve that long, lean look without dieting.
;) Rick
 
I don`t have photoshop(yeah, shocking I know...),but my scanner lets me resize to any dimension I want . I can scan an 8x10 and resize to 4x6 5x7...or whatever dimensions or fractions thereof I want. I can also crop, or not...Starting to love that scanner...Just gotta get a better Hard Drive,grrr....... L.
 
Good Feedback

Lots of good responses. I would like to respond to each:

1) Doug - How to crop is not the issue, Figuring out how much to crop quickly is the question.

2) Steve - the Proportion Calculator is 1/2 the answer, still a bit cumbersome to go to the website. I thought about writing a program, but I a sure it has been done. The key is a quick answer.

3) Dave - the equation is not difficult, I just used it as an example. This tells me how much to crop, which again is 1/2 of the answer.

4) Wally - it dont matter what the proportion is; what matters is the size the customer wants -- often cause they already have a frame. I have to prove to them that it may not work due to the cropping required to achieve the desired size.

5) Bill - the algebra method is the current method I use, but still is only 1/2 the answer.

6) Gumby - I agree practice makes it easier to resolve and I often "wing it" with the answer, but I could make a mistake.

7) Rob - I dont think I understand the Proportion Wheel. I am sure can look it up and figure it out. If I can input the dimension of the original photo and tell it size of one of the sides of the target enlargement, then hopefully it calculates the dimension of the second side, thereby telling me how much to crop. Again, this is 1/2 of the answer I need.

8) Photoshop Method - this will certainly work. However, I have to scan the picture, or take their digital file and load it into photoshop, which I find is time consuming at the sales counter.

9) Francisco - I do remember the Kodak sliding croptool. If I know the proportion of the new size, can I overlay the croptool on the original photo and visually see where the cropping will need to occur? This is what I really need.

10) Grey Owl - I do have my slide rule, but I dont see how it is the same a proportion calculator? Seems to me the slide rule worked on the principal of adding the equivalent logarithms of two number? Did I fall asleep during my algebra with slide rule class?

I really appreciate your responses. I will look into the Prop Calc Wheel. I think I would like to have something similar to the Kodak sliding crop tool. I dont know how it works. However, if I can use set the rectangle to the target proportion of the desired size, and if I could visually apply this right on top of the original photo -- then BINGO I have the right tool. For then, I could visually show the customer how much has to be cropped and the decision made on the spot. No scanning, no photoshop needed.

Still need help on this.

Ernesto
 
Got it! The Proportion Wheel will do the job. The answer is:

If I align the inner and outer wheels to the dimensions of the target enlargement size, then I simply read the scale of one of the sides of the original photo and it tells me the dimension of the second side. Then all I need to do is use a ruler to measure the second side of the original photo and this is the cropping line! This is quick and visual.

Yeah baby, this is what the Grumble is all about. Thank you Rob for turning me on to a tool that has been available for a long time. Remind me to buy you a beer at WCAF.

ernesto
 
Here's another item which will do the job visually.

http://www.bhphotovideo.com/c/product/154802-REG/Kalt_NPSH20.html

I use to sell both the C-Thru proportional scales and the Scaleographs.
If you buy a proportional scale buy the largest you can. I believe they are still made in three sizes. The smaller ones are difficult to read and won't give as precise an elargment or reduction percentage.

C-Thru #'s PS-69, 79 and 89 with 89 being the largest.
 
Ernesto, what are the sizes of the original photos that people are bringing in?

I have found them to be under 8x10 for the most part. What if you were to take a sheet of mylar and draw a 4:5 ratio box starting with a small dimension of 2" all the way out to 10" in 1/4" or 1/2" increments. I would put the bottom left at the same point. This way you could use this to over lap the photo and show cropping. Do the same for 5:7 , 11:14 and any other ratios that you might use.
 
I remember seeing a scaleograph many years ago at a photo lab.

The incoming photos are all over the place in terms of size -- sometimes, they are clipped. However, the main target sizes are 5x7, 8x10 and 11x14. So the mylar idea would be a good visual tool.

Great ideas and info, thanks.

Alright, two more beers for Dave M :beer: and Dave W :beer:

ernesto :beer:
 
Ernesto
What? Lets meet up for a beer too. I'll buy at Vegas.
I want to see your shop.
Francisco
 
echavez123 said:
Lots of good responses. I would like to respond to each:

...
10) Grey Owl - I do have my slide rule, but I dont see how it is the same a proportion calculator? Seems to me the slide rule worked on the principal of adding the equivalent logarithms of two number? Did I fall asleep during my algebra with slide rule class?

Ernesto
Click to expand...

Does your slide rule have a "C" scale and a "D" scale? [most do, but if yours doesn't the principle using other scales is the same, it is just that C and D are easier to read}.

I will use a simplified example where one side is 1 and the 2nd side is 2 (it can be 1" or 1 foot it does not matter).

Find "1" on the C scale and slide it so it is over "2" on the D scale. All numbers are now in proportion. So if you look at 2 on the C, you find 4 on the D; if you look at 3.5 on the C, you find 7 on the D. etc.

For more involved say one side is 3.5 and the other is 4.7, find 3.5 on the C scale and place over 4.7 on the D scale. Any numbers you read is now with this ratio. So if they want a maximum of 10" (the far right "1" on the D" scale, the number on the C scale is 7.45, so that would be the shorter dimension.

I hope this helps.
 
OK, so we found an easy low tech solution. The real question is how much do we charge for this service? How can we sell custom framing not work ourselves out of a job by selling ready-made frames. Was there not opportunity to sell a custom job here instead?

I am so very tired of the dummed down ready made everything we see today. Does the golden ratio have to be in only those ready made sizes? It's boring.
 
drandall said:
OK, so we found an easy low tech solution. The real question is how much do we charge for this service? How can we sell custom framing not work ourselves out of a job by selling ready-made frames. Was there not opportunity to sell a custom job here instead?

I am so very tired of the dummed down ready made everything we see today. Does the golden ratio have to be in only those ready made sizes? It's boring.
Click to expand...

Well first of all, we do lots of this type of work, and so the objective is to find a quick solution to the potential crop problem.

I find it difficult to sell a custom 8x10 frame. There are just so many ready-made choices. However, most of these ready made choices have no mat, and the customer is content to slap the photo against the glass. This is an opportunity to educate, and at least sell some custom matwork. I suppose we could do better if we displayed an 8x10 ready made with the photo stuck to the glass, and also have some custom 8x10 samples. However, this is chicken feed. The money is in the larger jobs, and we are content to do the enlargements and photo restoration.

Now if the customer asks, how big can this photo be enlarged, then we are talking a potential custom framing.

ernesto
 
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