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TECH TALK

 

I’ll guide you through all of the tech stuff below so no need to read all of this unless:

  >  You are curious about what all those letters dpi, tiff, jpeg, VOB really mean. 

  >  You are looking at other digital transfer services and need to understand the differences in what is being offered. 


Before diving in to Tech Talk I recommend first reading Plan Talk.

Photographs - DPI (dot per inch)

DPI is a measure of dot density, the number of individual dots that can be placed in a line within the span of 1 inch. Almost all of your photos were printed at 300dpi. Why would you want to scan a picture at 600 dpi if the photo is printed at 300 dpi? The quick answer is that higher resolutions, higher dpi, allow for higher quality printing and viewing of the digital image. 600 dpi takes longer to scan and produces larger files and helps ensure every detail in your print is recorded in digital form. I scan all photos at 600 DPI to ensure high quality scans. Any resolution over 600 dpi for printed photos is generally not needed unless it is a particularly important photo that some future generation may want to make into a very large print or if it is an important small photo as scanning a 2x3 print at 600 dpi will allow for a high quality 4x6 print, but a poor quality 8x10 print. If you have an important small prints I will scan those at 1200 dpi.


Slides and Negatives - DPI (dot per inch)

Slides and negatives contain much more detail than printed photos, so they need to be scanned at a higher dpi. In order to keep all of the details scans should be at least 3000 dpi and never less than 2000 dpi. I scan slides and negatives at 3200 dpi to ensure all details are captured. Unless your slides were taken with a professional quality camera and are in perfect condition, a scan over 3,200 dpi will show little or no improvement and can actually be worse as any slight imperfections (scratch, slight warping, etc.) will be captured at the higher dpi. 


File Types - Photos, Slides and Negatives

While there are many different file types the two that are most relevant to photo storage are TIFF and JPEG. TIFF (Tagged Image File Format) has no compression, no loss of fidelity. TIFF files ensure that no image data or picture quality is lost after scanning. Because no compression is used TIFF files are very large in size compared to JPEGs.  JPEG  (Joint Photographic Experts Group) uses a compression algorithm called lossy that reduces file size along with picture quality. In general file size is reduced by about 5 times while quality is reduced by about 20%. Applying image enhancement algorithms to a JPEG file can significantly improve the image quality by modifying the digital data of the image. 

Which is best? Actually both files are best based on the intended purpose, preservation or enjoyment. To capture all of the image quality to ensure future generations have the best possible image I to TIFF format.  Copies of the TIFF files can then be made to JPEG compressed format and enhanced. JPEG files can be uploaded to the cloud for easy sharing on the web.   


File Types - Video

Video Object (VOB) is actually a folder (not a file) that contains files in various formats in the from of DVD menu, audio, video, navigation content, and/or subtitles. I transfer most videos to a VOB folder with video file type of either AVCHD or AVCHD-SD to ensure as much original data is capture as possible, this results in large VOB files. A DVD with a VOB folder will play on DVD or BlueRay players and most computers. The VOB folder can be compressed and enhanced to a smaller MP4 file. 

AVCHD (Advanced Video Coding High Definition) is a file-based format for the digital recording and playback of high-definition video within a VOB folder. AVCHD comes in two formats: AVCHD (high definition) and AVCHD-SD (standard definition). The format depend on the videocam that made the recording most videocam recorded in standard definition; however, late model, high end videocams recorded in high definition. 

MP4 (MPEG-4) (Moving Picture Experts Group v. 4) - MP4 is the  international standard for audio-visual format and is viewable on almost any device and can be uploaded to the cloud for sharing. MP4 files compress the overall file size with little reduction in video or audio quality. MP4 files can be played on a wide variety of devises and shared over the web. I use the highest quality MP4 conversion parameters: H.264 MPEG-4 AVC (part 10), 29.97 FPS, SD, VBR 3000 - 3100 kbps for creating MP4 files.

The Cloud - What is the cloud? A cloud in the sky is made up of a mass of loosely bound water droplets where the shape of the cloud constantly changes based on atmospheric conditions. A cloud in the computer world is similar as it is made up of millions of connected computers spread across the globe. These computers are housed in large “computer farms” in a low cost manner. The size of anyone’s cloud presence (data storage) can constantly change based on needs. The cloud is so pervasive for data storage because of its flexibility and low cost.