Lightroom - Digital Negative Editor

Workflow difference between RAW (digital negative) editing and jpg/tiff (photo) editing

Photoshop Lightroom
Working File PSD file:
* original file
* editing layers
shared catalog:
* editing info for all library of photos (Catalog.lrcat)
* other info like library management (Catalog.lrcat)
* Preview of library (Preview.lrdata)
xmp file:
* editing info for its RAW file
(notes: catalog always have latest editing info, it need sync to update xmp file)
Output file jpg/tiff jpg/tiff
xmp: raw develop info
DNG raw file: raw with develop info embedded or original raw

* RAW file (like DNG) are not image file, it is a color data file with a small preview image embedded.

  • RAW file can be any bit, like 12-bit, 14-bit, 16-bit
  • jpg/tiff file are image file, it is exact what image data look like.
  • jpg is always 8-bit, tiff can be 8-bit, 16 bit

Data Structure in Lightroom Catalog and XMP

  • XMP file for each photo:
    • exif, iptc
    • keywords, rating
    • develop settings of RAW file
  • Catalog for library:
    • above as XMP
    • collection
    • keyword list
    • presets (import, develop, metadata, print)

Concept of Lightroom

  • it is more than a Digital Asset Management tool instead of a pure photo editing tool (like Photoshop)
  • Lightroom manage photos more like database server, instead file explorer in Photoshop
  • Lightroom “Import Photos” means “Register Photos” in Lightroom database = “its catalog”
    • Import notes: so if you “Import” from SD card, there is only one copy in your SD card, and if you delete SD card photos, then the photos are gone. only left a “low-res-preview” copy in the catalog.
    • That is why there is another option in Lightroom called “Copy”
  • Lightroom only manage its own database (the Catalog) file, the original photos are staying where they are on the directory that can be in any storage device.

key questions

  • Q: auto sync XMP file with catalog?
    • To assist in the sharing of the editing info to other App, Lightroom has an option to auto write info to .xmp (it is a per-catalog preference, so you can turn for per catalog base)
    • or you can manually update XMP by save, ctrl+s or (menu save metadata to file); Photoshop Camera Raw plugin will read the xmp file to do the changes
    • Camera RAW also save changes back to XMP file
    • also Lightroom doesn't use xmp file, it only use catalog file, so you need to import xmp file info back into catalog file. (menu: read metadata from file)
  • Q: where the retouch and painting layer stored?
  • Q: no need round trip to Photoshop? an fully replacement?
  • Factor: You can have many catalogs, like one catalog for each photo directory or each library linking to many directories
  • Factor: because catalog has a preview copy of the photos, so even when you have photos in other un-attached storage devices. at expensive of disk usage but it is automatically without need user involved

Big Disadvantage of Catalog Concept

You can't shift and move around those original photo directories

  • just like a web page link to the image directory, Lightroom catalog is pointing to those original photo directories,
  • once you move, you break the linkage in lightroom catalog database, and you have to re-link them, if you shuttle sub directory and name change, the process can be more detective and by how smart lightroom is.

Backup Original and Editing info always with concern to the catalog file

  • if your catalog don't associate with multiple devices for its photos, then it is easy to leave the catalog on each device, and re-point the device to update a backup copy
  • if your catalog links to multiple device, then in order to use that backup, you need to update the device list in catalog again.
  • so you can't use backup copys in lightroom before let it update the directory locations

It is a risk to put “All the eggs” in one basket

  • Lightroom used to get slow when the catalog grow over certain size, but now you have no limit in catalog size performance
  • However, the best practice with catalog may be “Each Catalog per Project”, just like “Each PSD per Photo”
  • In contrast, you may need to find a balance for your workflow, since there is always How Many databases you need to Manage “Personal, Shortlist, Best, Clients, Current Shoot, Tmp Edit”; that makes a point to decide whether you use lightroom or manage yourself with standard file explorer; and whether you need Lightroom to assist you on photo management
  • also, in single catalog, if you run out of disk space as catalog grow, you can't add into the catalog anymore, and you can only continue to use lightroom if you change to a bigger disk.
  • so instead of many photo directories, you manage many photo catalogs

Your are forced to backup everything again and again if you use single catalog

  • not all photos are on the same level of importance, I may only like to backup certain photos not all every time
  • all your changes are in one file, you have to roll back all photo changes in catalog if only one change is corrupted.

No advantage clone retouch heal combination

No Layering and Compositing

Single User workflow, Catalog can only be changed by single user compared to normal folder structure


  • Year_Folder
    • Date-Project_Name
      • shortlist_folder
  • Best_of_Best
    • catalog file for search
    • album_name

Advantage of Lightroom Catelog system

Deal with multiple Cameras and multiple Photographers for single project

  • automatically figure duplicate names from different camera sources. (use Lightroom import)
  • automatically avoid duplicates from same SD card again and again

rating system

batch processing for large photo pool

multiple collections without duplicate folders

Breaking Point with Lightroom ?

What is equivalent workflow in lightroom?

  • in Photoshop, the process flow is
    • Original Photo layer → Retouch and Fix with original layer → Color and Exposure Grading layer
  • the above workflow in Photoshop will break if flow like below
    • Original Photo layer → Color and Exposure Grading layer → Retouch and Fix with original layer
    • since every color change, the retouch and fix clone won't carry over those color change and still with previous color version; as behind the scene, you are painting pixels, and photoshop layer only record the result pixel, not the brush stroke motions and steps; and also color grading got baked into retouch and fix layer
  • quote: “If you did the color treatment or color grading first in your workflow and then the client didn't like it, or wanted changes it could be an issue with all your subsequent cloning, healing, copying image parts done down the line. All those layers would have to be re-done to match the color change.”
  • appwiki/lightroom.txt
  • Last modified: 2021/08/28 08:21
  • by ying