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Increase dpi?

Apr 15, 2013, 17:28
Post: #1
Increase dpi?
I want to convert an image from it's current resolution of about 72 pixels per inch to 600 dpi. How is that done? This project is for a corporation seal which measures 1.5 inches per side. The stamp maker needs a .jpg at 600 dpi.
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Apr 15, 2013, 22:23 (This post was last modified: Apr 15, 2013 22:23 by Neil2013.)
Post: #2
RE: Increase dpi?
I only have the image I have and cannot get another. It's free clipart. The original is a .gif. Can Inkscape do the 600 dpi with that?
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Apr 16, 2013, 09:34 (This post was last modified: Apr 16, 2013 09:42 by rich2005.)
Post: #3
RE: Increase dpi?
Post a link to the gif or better post it here. Inkscape can 'trace' a bitmap or maybe possible to create from scratch in Gimp using the paths tool. Depends on the image.

When you say a 'stamp' is this a physical stamp ie. apply ink with an inkpad, and hit a sheet of paper. Makes it easier if colour is not involved only an outline.

edit:
This is the sort of thing you might be looking at doing. This is not Inkscape it is command line using a little application potrace and GIMP
http://youtu.be/bhHACVo_pKE
another alternative is an online converter
http://image.online-convert.com/convert-to-svg
you will lose colour with this one

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Apr 16, 2013, 15:50
Post: #4
RE: Increase dpi?
Image as .png attached. I don't find a .gif. I made a .svg, but it's not as crisp as this image.


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Apr 16, 2013, 17:44
Post: #5
RE: Increase dpi?
(Apr 16, 2013 15:50)Neil2013 Wrote:  Image as .png attached. I don't find a .gif. I made a .svg, but it's not as crisp as this image.

Still not sure what you want, a postage stamp?

Your image scales reasonable well with a stair resize, using something like this plugin
http://registry.gimp.org/node/26196

Do you want the colours smoothing perhaps?


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Apr 16, 2013, 17:53
Post: #6
RE: Increase dpi?
This image will be used in a size approx. 1.5" to 2" in diameter. The stamp maker requires black and white line art only. At 600 DPI, only. It's there requirements.
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Apr 16, 2013, 18:03
Post: #7
RE: Increase dpi?
(Apr 16, 2013 17:53)Neil2013 Wrote:  This image will be used in a size approx. 1.5" to 2" in diameter. The stamp maker requires black and white line art only. At 600 DPI, only. It's there requirements.

You want something that will be used to engrave a stamp ( that was what I asked first time) . Please define stamp.

Is it just the outline or do you need some of the texture, like banknote engraving.

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Apr 16, 2013, 18:13 (This post was last modified: Apr 16, 2013 18:28 by Neil2013.)
Post: #8
RE: Increase dpi?
Stamp as in embosser for paper. Please see Staples link:

http://www.staples.com/sbd/content/copya...d=embosser

The paper is inserted and when the handles are squeezed, the "stamp" cuts (embosses) into the paper, leaving the image behind as "raised" image on the paper.

Yes, like banknote engraving.
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Apr 16, 2013, 18:44
Post: #9
RE: Increase dpi?
(Apr 16, 2013 18:13)Neil2013 Wrote:  Stamp as in embosser for paper. Please see Staples link:

http://www.staples.com/sbd/content/copya...d=embosser

The paper is inserted and when the handles are squeezed, the "stamp" cuts (embosses) into the paper, leaving the image behind as "raised" image on the paper.

Yes, like banknote engraving.

Do not think much in the way of banknote engraving will be possible but:

I know what you mean. It is a seal. I have one, first time it has seen the light of day for many a year. Looks like this http://i.imgur.com/5lsGyHf.jpg and is 40 mm in diameter.

Since it is for embossing paper IMHO it will have to be extreamly simple, heavy lines, just the outline.

Will have to think about best way to go for this one. aka there is a tv program I want to watch.

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Apr 16, 2013, 19:11
Post: #10
RE: Increase dpi?
Nice seal. No worries, mate. I'll be back when you have time. Thanks.
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Apr 17, 2013, 00:16
Post: #11
RE: Increase dpi?
I tried the file converter website. It's wonderful. It won't work here, however. The company that makes the embosser stamp says: black & white line art - NO shading. Thanks.
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Apr 17, 2013, 10:05 (This post was last modified: Apr 17, 2013 10:20 by rich2005.)
Post: #12
RE: Increase dpi?
@Neil2013
Personally, I do not think this image will work. Have a look at this site, it has a good description of what you might expect.

http://www.rubberstamp.uk.com/EmbossingPresses.php

I think you are hoping for a result like the last option: Contoured - hand engraved
Whereas what you are going to get is the second option: Image is machine-engraved from black-and-white artwork, with all parts of the image embossed to the same height.

I had a stab at it: After a bit more scaling and quality not required because what you need is a "binary" image, pure black and white. Easy to get, change the image mode to indexed, choose black and white (1 bit palette), ok it, then reverse the process and change the image mode back to RGB.

Nice result but IMHO no good for engraving, far too much fine detail.
I think you need to be looking at zones, black for raised, white for not raised, and each zone will have to border the opposite colour to get an effect. Not too much detail either.

I came up with this, & printed it to compare with a 'real' seal.
http://i.imgur.com/nXrMCBK.jpg Try and imagine 'raised and 'not-raised' (unintended consequence perhaps - looks like the joker is giving you the finger lol.)

If you want to play with this it is attached.

The other thing I think on a practical note, the portrait is full face, much easier to represent a head on an engraving if it is in profile. Look at the head on a coin. Plus of course you need something really simple.

best of luck,


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.xcf  foolredcapandbellslayers.xcf (Size: 1.59 MB / Downloads: 87)

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Apr 17, 2013, 11:42
Post: #13
RE: Increase dpi?
You can't really get a true impression (pun unintended) with a bump map
There will be borders high/low as

[Image: ZrgYVFr.png]

but yeah, what do you with facial features and a relatively coarse engraving method.

Looking at my real stamp, the engraving is not straight up and down, (otherwise it would possibly guillotine the paper) there is a bevel which might take some of the coarseness away.

I still think a head in profile would be the best way.

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Apr 17, 2013, 13:48 (This post was last modified: Apr 17, 2013 13:51 by rich2005.)
Post: #14
RE: Increase dpi?
Well there is no colour involved, just either up or down, but in normal room lighting the embossing is plain to see.

Just for info, this is one half of the die. The best half ie. the engraved half is stuck in the press and I assume this was cast from that.

[Image: L4pJmDE.jpg]

You can see the bevelling and I assumed that the smallest "line" would be about 1 mm say about 23 pix @ 600dpi
The divisions on the scale are 1mm by the way, it is part of a vernier.

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Apr 17, 2013, 21:56
Post: #15
RE: Increase dpi?
Thank you for so very much help.
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