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Application Guide Adobe Illustrator
Linked image - Resolution of Image Files
Resolution stands for the fineness of an image. The unit of dpi(dot per inch) and ppi(pixel per inch) are used. In Photoshop, it is written as ppi. However, it is common to called dpi.
Originally, the resolution of the image itself is 'ppi,' and the resolution for output such as printing is 'dpi.'
It shows how many dots there are in 1inch(=25.4mm). The more dots there are, the more the image is high-definition for the high density of the pixel.
- *The resolution good for printing is from 350 to 400 dpi.
- *200 dpi is fine for posters because they are seen at a distance. (The large-sized image of 400 dpi is too big, so that it would be hard on working environment.)
- *72 dpi is display resolution used in web sites often. Although the images of 72 dpi are fine on the monitor, it is not enough for printing. The printing might be grainy and has visible dots, and the texts might not be readable.
Make sure that your Photoshop data has a proper resolution for printing (from 350 to 400 dpi).
▼Resolution for each use
|71〜96 dpi||display resolution|
|200 dpi||could be used for poster printing|
|350〜400 dpi||proper resolution for printing|
How to check the resolution
1. Check with Photoshop(Check the resolution of the original image)
[Image] menu > [Image Size]
You can check the resolution of the image in the size you want to use for by unchecking the [Resample image:] and enter the [Width:] and [Height:] size you need.
Conversely, you can know the properly size for offset printing by filling [Resolution:] between 350 and 400 pixels/inch.
2. Check with Illustrator
(Check the resolution after placing the image on Illustrator document)
After scaling the image in the actual size you need, check the resolution in that size as follows:
Select [Window] menu > [Document Info.] Choose [Embedded Images] at option menu.
Too much scaling on the Illustrator causes the image deterioration and make your print data file heavier. We recommend you to modify the image on the Photoshop in advance and try to use in the same size or keep the scaling on Illustrator around 70%〜130％.
- ※It is ideal that the resolution in Photoshop is the same number as the resolution in Illustrator.
Image resolution and size change (in Photoshop)
When you want to use the digital camera data for your prints, sometimes the original data has too high or low resolution. We guide here how to adjust the image to proper resolution data by pixels complement.
1. [Image] menu > [Image Size]
2. Uncheck [Resample Image:] and enter the size for printig in the box of [Width:] or [Height:] in [Document Size].
3. Check [Resample Image:] and enter the proper resolution.
Photoshop complement the pixels without changing the data size.
You can also change the data size without changing the image resolution in the same way.
Trying to enhance the image or size means that supplement the pixels.
It is difficult to avoid completely the deterioration of the resolution.
We recommend to prepare the larger size images than the size you are going to use.
You can choose how to fill pixels by the option.
- This is the advanced way to fill pixels of the neutral color by measuring the color around them.
- This is the middle way between Bicubic and Nearest Neighbor. The number of pixels to be measured is smaller than Bicubic, therefore, the processing time is shorter.
- ・Nearest Neighbor
- In this way, new pixels are not produced and the pixels of the nearest color are placed instead. Although the line of the image is jaggy, it is sometimes effective for resizing the line-art image.
- ※Often resampling image cause the degradationof the image.
Make the image size and resolution proper at one time.