A digital photo is primarily a computer file, consisting of 0 and 1. Your device converts the image into digital data and then saves it for storage. Most cameras use the JPEG format, others offer you, in addition, TIFF or RAW. What are these formats and how to use them?

Use digital images in 7 points

1. Save the original file

2. Ensure high resolution of digital files

3. Avoid using images from the Internet or electronic documents

4. Integrate the logos without modifying them

5. Think about the colors

6. Provide the correct image files

7. Make use of photo stocks

The publications, especially the popularization documents, contain images: photos, graphics, drawings, diagrams, maps … These images are saved in file formats digital devices with various characteristics: 

  1. Save the original file

Warning: before manipulating your illustrations files (photos, graphics, scanned drawings, diagrams, cards …), always save the original file of the original image.

  1. Watch for the resolution of the image

The digital image is formed of a set of points, or pixels. The resolution – high or low – or definition of the image is measured in dots per inch (dpi), dpi (dot per inch), or ppi (pixel per inch). More the image contains pixels, plus it can be printed in large dimensions.

The number of pixels induces the weight of the image, as well as its physical size (according to the resolution of the output device). To get the correct impression, choose a resolution of at least 300 dpi. The resolution information of a digital file is contained in the properties of the image files, in the form of “dimensions” of the image and “size” of the file. 

  1. Avoid using images from the Internet or electronic documents

To lighten the files, most websites and many electronic documents created with a word-processing or slideshow software use small and weak images resolution. Avoid using them: they are not printable or displayable in full screen. Better search for the high resolution digital files on photo stocks. 

  1. Integrate logos without modifying them

A logo is a protected image that must be integrated as it is, without modifying its text, form and colors. Logos can be downloaded from the Internet if you use them in small size electronic document. If you want quality printing or if you use them for large documents, ask for high resolution files.

  1. Think about colors

If the print or on-screen display is black and white, you can choose between the two types following pictures:

1. a grayscale image

2. an image in 2 levels, black and white 

Compression of high resolution digital file

A digital image is divided into points called pixels, abbreviation of “PICture ELement”.

Each pixel contains two pieces of information:

• its position in the image

• its color

The quality of the image depends on:

• number of pixels

• the finesse of the color palette

The higher the quality of the image, the more information that defines it … and the larger the file size.

Compression reduces the weight of your image files when you save them. It implies a certain loss of information, and therefore a decrease in the quality of a high resolution image. Each format presenting its specificities, it is the destination of your photographs which must guide you.

JPEG was created specifically for the transmission of photographic images. His compression principle is based on the fact that the eye is less sensitive to changes subtle colors that variations in brightness. This allows him to discard a certain amount of data so that the amount of information defining the image decreases.

The JPEG format compresses the image by degrading it (smooth colors). You can choose the rate of compression in the photo processing software: the lower it is, the more faithful the image, but the more it is heavy. Warning: once the image is compressed, it is impossible to restore its initial quality.

Organize your photos stock

“The photo is a piece of time that one appropriates”

1) Durability of the image: paper support (some decades) or megabytes (indefinite if support renewal).

2) Organization of the memory.

3) Rights (legality) of this appropriation.

1) Solve a serious “mess”: hard disks, USB keys, SD cards, software libraries ….

2) Find the photos you have in mind

3) Organize the photos selected according to individual criteria (themes, dates, box settings, …)

4) Select a set of photos to create a slideshow, a book, an exhibition, …

5) Save this stock in order.

6) Limit the expense in storage memory, software and lost time in search.

Structuring the memory of time

Organize your photo stock of sorted and improved photos request software tools.

1st software: save the selected photos

 – Choose the final recording format: jpg and / or tif according to the qualitative value of the photo; the tif format is heavy, but respectful of the integrity of the image, which allows subsequent adjustments.

 – The treatment by group of photos is imperative. The free software mac or pc are numerous.

2nd software: organize the photo stock: Have digital resource management software (photos) allowing their classification and recovery at using keywords assigned individually. A cloud storage finds and returns the photos according to the chosen filter (date, themes, keywords, metadata sometimes).