Participant

Question

Skalierung nicht korrekt

Forum|Forum|4 years ago
January 16, 2022
3 replies
562 views

Hallo

Ich habe ein Problem mit der Skalierung in AI.

Mein Vorgehen:

Bild mit einem HP Scanjet 4600 mit 600dpi einscannen und als TIFF speichern.
Bild im AI 26.0 öffnen und von Hand vektorisieren um dann Schablonen für Airbrush von meinem Schneideplotter Mimaki CG SR III schneiden zu lassen.
Vektorgrafik mittels dem Plugin FineCut 9.2 zum Plotten schicken.

Der schneideplotter schneidet die Form absolut korrekt aus, nur stimmt die Grösse bei weitem nicht.
Im AI wird mir die Objektgrösse korrekt an gegeben und in der Schneidesoftware auch korrekt übernommen.

Was mir noch aufgefallen ist; ich habe mehrere Bilder genau gkeich eingescant und dann geöffnet und bearbeitet. Allerdings erscheinen mir die auf dem Bildschirm jeweils mit erheblichem Unterschied in der Grösse.

Kann mir jemand einen Tip geben wie ich dieses Problem beheben kann?

This topic has been closed for replies.

C

Christian22677547hvp5Author

Participant

Hello colleagues

Thank you very much for trying to help me.

But I guess I am a lost case. Since 1h I try to arrange between pixels, mm and so on. AI is doing what she wants, no chance for me.

I remember the times I worked with my Atari ST 35 years ago, I dont remember the name from the software, but it was easy to handle intuitve, no online help, but it worked. With AI I am not on a familar way.

absolutly disapointet greetings

Christian

Jacob Bugge

Community Expert

Christian,

I certainly believe it is worth pursuing this further.

A few questions based upon these observations,

What else I noticed; I scanned several images exactly and then opened and edited them. However, they appear to me on the screen with considerable difference in size.

... As I changed the one side to 7014, than the other side switched to 4962,16. That looks correct for me. But than the cutout from my cutter was totally wrong again, something about 3x bigger than expected.

Can you give the following answers for one or more sets of corresponding sizes of different images, where each set consists of the same image scan all the way from 1) to 3)?

1) Scan image from the HP Scanjet:

Am I right in believing that you scan A4 size = 210 x 297 mm?

Are you sure the resolution is 600 PPI for all images?

Is the TIFF image size 4960 x 7014 pixels in all cases, or which sizes?

2) Placed image in AI:

Are you getting the A4 size, or different sizes when placing different images scanned in A4 size (Transform panel)?

Which size (in mm and pixels)?

Which unit are you using in the document(s)?

3) Resulting artwork in AI (presumably within the placed image size/Artboard):

Am I right in believing that the resulting artwork in AI is purely vector and therefore independent of the pixel x pixel size of the scan image, so that only the actual artwork size (in mm or pixels) matters?

Which actual size?

4) Cutout size from Mimaki cutter (corresponding to the resulting artwork size in AI):

Which actual size?

I believe those answers might give the clues needed.

It is (also) getting late here, soon time to attend to other duties in the dark hours, before the sun rises.

Met1

Legend

Although I am using Fine Cut 9 (2.1) with Illy 26.0.2 with no issues, it does say on their website that this version of FC is not compatible with Illy 2022...

Met1

Legend

One more thing, are you running out of a standard size Illy doc (less than 227inches?) or is it a "large-size" canvas (bigger than 227inches or equiv unit). It shouldn't be an issue, again mine still works fine, although with the large doc it is scaled to 1/10th doc size.

Jacob Bugge

Community Expert

Christian,

When you open the images in AI, is the right/expected size in pixels x pixels showing in the Transform panel (Width and Height)?

Obviously, that is what determines the size(s) of the object(s).

Otherwise you will have to scale to the right size.

Which size(s) are you scanning, and which show(s)?

C

Christian22677547hvp5Author

Participant

Hello and thank you for your answer.

That sounds really logical and I tried it out.

The size was not that what I expected. My scan in TIFF was 4960 x 7014 pixels.

The picture than in AI something completely different. As I changed the one side to 7014, than the other side switched to 4962,16. That looks correct for me.

But than the cutout from my cutter was totally wrong again, something about 3x bigger than expected. 😞

Jacob Bugge

Community Expert

Christian,

The size of raster images can be expressed in the simplest/safest way as just a size in pixels x pixels, or as a size in inches (or whatever) and a resolution (PPI).

The latter can cause some strangenesses.

Hence my question about the size of the image in AI.

My guess is (about) 595.2756 x 841.8898 pixels, corresponding to an A4 (portrait) shown (best possible) at the actual A4 size, which is measured in mm.

This would mean that the image appears as it would if the resolution had been 72 PPI, but it still contains the 600 PPI resolution, so you can just scale up the image, and make the needed amendments to end up with whole pixel values.

The scaling can be done by selecting the scanned image and then adding /0.12 to the value in the W or H box in the Transform panel and press Ctrl/Cmd+Enter to keep proportions, and then afterwards round the values of W and H to the nearest integer (up or down) or to preferred values close to them; the latter can be preferable if you wish to scale to some other size and still have integers.

It might look something like this:

W: 210 mm ~ 595.2756 pixels > 595.2756/0.12 ~ 4960.63 to be rounded to 4961, or to 4960

H: 297 mm ~ 841.8898 pixels > 841.8898/0.12 ~ 7015.748 to be rounded to 7016

4960 and 7016 can work well together for a number of other sizes, and you can also make small changes for the final size without anyone ever knowing.

0.12 = 72/600 so it is the accurate way of scaling up from the smaller 600 PPI size to the larger 72 PPI size.

In AI, pixel is a unit with a value of 1/72 inch just as the point.

As you can see, the numbers are close but a little bit different, which will always be the case when converting between mm and inches/points/pixels.

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