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Presentation on digital photography I gave in 2005 at the Saratoga Library.TRANSCRIPT
- Digital Photography I The Basics Peter Liu Photography kaiscapes .com
- Photography
- From two Greek words meaning drawing with light:
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- phos ("light")
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- graphis ("stylus", "paintbrush")
- Merriam-Webster:
- The art or process of producing images on a sensitized surface (as a film) by the action of radiant energy and especially light.
- Photography
- The art of capturing light as it falls on a subject or scene, and rendering it so that your viewer is moved by the result.
- Capturing Light
- Hard Light high contrast, well-defined shadows
- Capturing Light
- Soft Light diffused, rich colors
- Capturing Light
- Overhead Light harsh shadows
- Capturing Light
- Front Light flat, lacks dimension
- Capturing Light
- Side Light evokes mood, accentuates shapes
- Capturing Light
- Back Light may need to fill, makes silhouettes
- Capturing Light
- Overcast Light low contrast, muted shadows, good for detail
- Characteristics Of Light
- Quality
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- The smaller the light source, the harder the light appears
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- The larger the light source, the softer the light appears
- Direction
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- Determines where shadows fall
- Contrast
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- Difference between the lightest and darkest tones of the subject or image
- Source
- Ambient daylight, tungsten, flourescent, firelight
- Artificial flash, tungsten
- Intensity
- Reflectance
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- Reflectivity of the subject
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- Intensity of the light source
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- Angle of view
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- Distance of light source
- Fall-off
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- Increase distance, decrease light level (Inverse Square Law)
- Characteristics Of Light
- Color
- Mixture of primary colors: Red, Green and Blue varies according to source
- Warm predominantly red
- Cool predominantly blue
- Expressed in Kelvin (K):
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- Incandescent ~ 3000K
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- Fluorescent ~ 4100K
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- Flash ~ 5400K
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- Daylight
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- Direct Sunlight ~ 5200K
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- Cloudy ~ 6000K
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- Shade ~ 8000K
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- Referred to as White Balance in digital photography.
- White Balance 4100K ( Fluorescent ) 3000K ( Incandescent ) 5200K ( Sunlight ) 8000K ( Shade ) 5400K ( Flash ) 6000K ( Cloudy )
- Why Are You Telling Us All This??
- Because good photography depends on being able to execute two things well:
- Exposure
- Composition
- Exposure
- A combination of three factors sometimes known as the Photographic Triangle:
- Shutter Speed
- Aperture
- ISO
- Or
- how quickly light is being captured through how big an opening onto how sensitive a surface
- Shutter
- A cameras shutter covers the hole through which light enters to expose the sensor or film.
- Shutter Speed Fast
- 1/1600 sec., stops action
- Shutter Speed Slow
- Silky, cool, edgy effects
- Shutter Speeds
- Open too long, photos are washed out (overexposed)
- Not long enough, photos are too dark (underexposed)
- Expressed in seconds: 1/8000, 1/4000, 1/2000 1/1000, 1/500, 1/250, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1 second, 2 seconds, etc.
- Each setting is half or double the speed of its neighbor.
- As the amount of available light decreases by half, the shutter speed needs to slow by double.
- As the amount of available light increases, the shutter speed needs to increase
- Aperture
- The opening through which light enters the camera.
- Aperture
- The size of the opening is expressed as an f-stop number : 1.42.02.845.68111622
- Each number represents an opening size that is half or double its neighbor
- The larger the number, the smaller the opening
- For all the science types: the f-stop is actually a ratio between the diameter of the aperture in the lens and the focal length of the lens:
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- e.g. f/2 on a 50mm lens says the aperture is 25mm. 50/25 = 2.
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- (Source: A Tedious Explanation of the f/stop by Matthew Cole)
- For the rest of us: the size of the opening controls the depth of field in the photograph.
- Aperture And Depth Of Field
- f/5.6
- Shallow depth of field
- Aperture And Depth Of Field
- Caused by refraction of the light hitting the edge of the opening
- Rays scatter and overlap instead of going straight on its way to the sensor or film
- The camera sees multiple images, resulting in blur.
- The smaller the opening, the less surface available to scatter the light, resulting in less blur.
- Bottom line: the aperture is used to control how much of the scene is in focus.
- Aperture And Shutter Speed
- The following reciprocals will yield the same exposure:
- What changes is how much is sharp and in focus.
- The Light Meter
- A device that assesses a scene and figures out the correct exposure
- Modern cameras have them built-in
- External handheld models also available
- Engaged when shutter is pressed halfway
- Matrix/Evaluative, Center-weighted, Spot metering
- Looks for 18% Grey or Middle Grey
- Easily fooled!
- Tricky Metering Situations
- Exposure Compensation
- Used when the light meter is unable to evaluate the exposure as desired, or when correcting by whole stops is too much
- Usually +/- 2 EV (Exposure Value) in steps of 0.3 EV
- Available on most cameras
- ISO
- Sensitivity of the sensor or film to light
- Represented by a number assigned by the International Standards Organization (hence, ISO) 100, 200, 400, 800, etc.
- Again, each number represents double or half the sensitivity of its neighbor (Aint it wonderful!)
- The higher the number, the more sensitive to light
- Digital photography is cool because you can change the ISO from shot to shot!
- Higher ISO = More Noise!
- ISO 3200
- So
- Exposure depends on:
- Shutter Speed how fast
- Aperture how much
- ISO how sensitive
- And color is a function of:
- White Balance how hot
- And
- Which camera you choose is a function of how much you want control those factors!
- Cameras
- Two popular types of cameras on the market for the consumer
- Cameras
- Point-and-shoot
- Viewfinder separate from lens
- Small and compact
- Fixed lens
- Shutter delay
- Usually fully automatic (some exceptions, like Olympus C-series)
- SLR (Single-lens Reflex)
- Based on 35mm design
- Actual image seen in viewfinder
- Interchangeable lenses (more flexible composition)
- Ability to use filters
- More advanced metering and shutter system
- Little to no shutter delay
- Automatic, Program (Scene), Shutter Priority, Aperture Priority and Manual modes
- Flash hot shoe
- Pro models may not have pop-up flash or Program (scene) modes
- Point-and-shoot Anatomy
- Viewfinder separate from lens (better to use LCD on digital)
- Actual image (as exposed) is not quite the same as in the viewfinder
- Much simpler design than SLRs.
- SLR Anatomy
- Through-the-lens (TTL) viewing (works like a periscope)
- Actual image (as exposed) is shown in the viewfinder
- Mirror flips up when the shutter release is pressed, exposing the sensor (and blacking out the viewfinder)
- Reflex comes from the use of the mirrors in the viewfinder system.
- Advantages Of Digital
- Instant gratification (big fun factor) see your images right away
- No film cost shoot as many as you want, erase and shoot again (heck, its just pixels!)
- Convenience print, email, web, slide shows; no waiting around for the photos to come back from the store
- Easier to make copies no need to send (or lose) originals
- Easier to manipulate no scanning required (you did that when you pressed the shutter)
- No need to spend hours in the darkroom
- Black-and-white just shades of grey colors
- No worries about film fading over time; digital images last for as long as your storage media doesnt die on you
- Less storage space no physical shelves to keep stacking
- Metadata information available for indexing and cataloging.
- Disadvantages Of Digital
- Image quality
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- As good or better than 35mm in the right hands , but cannot compete with medium or large format film (yet)
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- 1.5x cropping factor or focal length multiplier in SLRs due to smaller sensor
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- Exposure much more critical 1/3 stop subtle in Velvia, but blatant in digital
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- Blown highlights no information means no information; film is better at rendering overexposed areas more naturally
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- Great shadow detail, but clipped highlights -- traded highlight detail for lower noise; most likely need to underexpose and correct in post
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- Skilled user needed to extract the image quality equivalent to that of good film
- Very different workflow requires skill with computers and software, knowledge of color management and printing, web, email, etc.
- You are the photo lab youve traded darkroom chemicals for a digital darkroom
- Easy to lose images memory cards can become corrupted in-camera; photos are scattered all over your computer; hard drives die
- Slow camera is locked up once the buffer is filled until the images are completely written to the card
- Shutter delay (point-and-shoot)
- Digicams are much more expensive than film cameras and become obsolete sooner
- Slide shows projectors designed for business graphics render poor photographic quality and awful color.
- More megapixels = bigger files = more storage + faster computers
- Which Is Better?
- The apple or the orange?
- Each has their respective strengths and weaknesses.
- It all depends on what youre trying to accomplish.
- Everything in photography is a trade-off.
- Choosing A Digital Camera
- The number of megapixels isnt everything!
- More is not necessarily better,
- But more can be an advantage when cropping or printing big.
- Megapixel Madness
- How Many Pixels Do You Need?
- Assume 300 dpi (dots per inch) for a good quality print on a desktop printer
- Break down megapixels to length and width, then divide by 300
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- e.g. 6MP ~ 3008 x 2000 pixels (Nikon D70)
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- 3008/300 = 10.027 in.
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- 2000/300 = 6.667 in.
- BUT, different printers have different requirements
- Software can help upsize or downsize with varying results
- Large fudge factor, depending on chosen application and printer technology.
- Digital Camera Resolution Chart (Source: B&H Photo-Video-Pro Audio )
- So, How Do I Choose A Camera?
- Ergonomics how does it feel in your hands?
- Size and weight of the camera
- Size and quality of the LCD
- Lens quality
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- Sharpness
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- Distortion
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- Zoom capability (optical vs. digital)
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- Digital zoom is evil!
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- Metering capability
- Built-in flash
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- Red-eye reduction
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- Can you control it?
- Manual capability vs. automatic or program modes
- Battery life
- Media type
- Decide whats important to you based on how youll be using it!
- About The Cards
- Pick One
- I Bought A Camera Now What?
- Charge the battery
- Format the card
- Set up the camera
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- Date and time
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- Bells and whistles (literally!)
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- Digital zoom if you can turn it off, do it!
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- Mode: Auto, Program, Aperture Priority, Shutter Priority, Manual
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- ISO
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- White balance
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- Color space (Never mind!)
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- Image quality and file type
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- JPEG (Joint Photo Experts Group) in-camera processing, lossy (small, medium, large), 8-bits (256 shades of color) per channel (16.7 million colors)
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- TIFF (Tagged Image File Format) in-camera processing, uncompressed, lossless, 8-bits per channel
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- RAW direct output from the sensor, little to no in-camera processing, 12-bit (4096 shades of color) per channel (68.7 billion colors)
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- What are you waiting for?? Go shoot pictures!
- Recall
- Good photography depends on being able to execute two things well:
- Exposure
- Composition
- Composition
- The art of including the essence of what moves you about the scene in your photograph, while excluding any non-essential, distracting elements.
- Composition
- There are established guidelines, but ultimately, its about your artistic vision
- Very subjective
- Not always a conscious thing listen to your heart!
- Simplify, Simplify, Simplify!
- Simplify
- Simplify
- Simplify
- Simplify
- Simplify
- Simplify
- Composition
- You take the picture, but you make the photograph.
- Its about seeing the photograph in front of you.
- Its about design arranging all the elements of the scene in your viewfinder so they become something compelling to look at.
- Hold the viewers attention as their eyes travel around the frame.
- Check your corners! Move your eye around the frame in the viewfinder looking for anything that might distract attention away from your subject(s) a stray branch, somebodys toe, etc.
- Our eyes are naturally drawn to brighter, hotter elements. If those arent your subject(s), exclude them!
- Composition
- Do in in the viewfinder, not in Photoshop! Its always best to start with a good image.
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- Photoshop doesnt make a bad photograph good, it makes a bad photograph big.
- Youre rendering a 3-D scene as a 2-D print. Frame it carefully!
- Try not to bullseye your subject in the frame. Dead center is deadly!
- Use the Rule Of Thirds the oldest trick in the book for composing a visually balanced and pleasing image.
- Rule Of Thirds
- Divide your scene into an imaginary tic-tac-toe grid, then place your subject(s) near any of the four intersections
- Use Those Lines!
- Diagonal lines are especially dynamic. Use them to lead the viewer to the subject, guide the viewer across the frame or create vanishing points.
- Find Grace
- The S-curve is a classic compositional device to create a sense of grace.
- Tips For Better Composition
- Try not to cut off any body parts.
- Dont have trees or telephone poles growing out of your subjects heads.
- Tips For Better Composition
- Tell a story with your photographs
- Learn, Practice, Then Forget
- Remember, these are just guidelines, not hard and fast rules.
- Now That You Have Your Pictures
- Time for the workflow
- Why do you need a workflow?
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- Because your photos are trapped in your card and somebody has to liberate them
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- Because its too expensive not to get them out and print/email/put-them-on-the-web yourself
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- Because you want artistic control over how your photos are displayed
- Now That You Have Your Pictures
- Typical Post-capture Workflow:
- Download And Store
- Downloading directly from the camera can be slow
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- usually USB 1.1 maximum transfer rate of 12Mbits/sec.
- Use a fast external card reader if possible
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- USB 2.0 capable of up to 480Mbits/sec.
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- Firewire (IEEE 1394) capable of up to 400Mbits/sec.
- Software available to download, rename, add metadata
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- Downloader Pro (Breeze Systems)
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- Photo Mechanic (Camera Bits)
- File naming is important.
- Use the same file naming
- scheme for your edits and originals.
- Metadata is essential. Help
- yourself find and figure out your photos later.
- Backups! Backups! Backups!
- Copy your newly downloaded images first thing before you do anything else!
- The Browser
- Allows you to look at all the photos on your computer
- Thumbnails and previews
- Sorting, ranking
- Batch renaming
- Manage metadata
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- EXIF (Exchangeable Image File Format)
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- IPTC (The International Press Telecommunications Council)
- Popular software packages have them built-in
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- Adobe Photoshop
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- Photo Mechanic
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- iPhoto
- The Organizer
- Builds databases of information about your photos
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- EXIF
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- IPTC
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- File names
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- Folder names
- Allows searching of your photos regardless of where they are
- Popular software
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- Adobe Photoshop Elements
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- Extensis Portfolio
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- iView MediaPro
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- Canto Cumulus
- Time To Edit
- Crop and straighten
- Tone and contrast
- Color correction
- Creative sharpening
- Many software packages available:
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- Adobe
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- Corel
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- Apple
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- Microsoft
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- Extensis
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- Ulead
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- JASC
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- Nova
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- Free/share-ware
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- Etc.
- Why Adobe Photoshop?
- Because its the best!
- Because the camera is good, but you might be able to do better in post
- Because your in-camera technique is good, but you might be able to do better in post
- Because you might have been forced to do something like underexpose on purpose, and only you know how to deal with that
- Why Adobe Photoshop?
- Because you may want to create a piece of art out of your photos
- Adobe Photoshop Family
- Adobe Photoshop Album 2.0 casual snapshooters
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- Adobe Photoshop Album Starter Edition 3.0
- Adobe Photoshop Elements 3.0 photo enthusiasts and most amateur photographers (This is probably all you need!)
- Adobe Photoshop CS2 professional gold standard
- Sharing Your Photos
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- Desktop printers
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- Commercial printing services
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- Shutterfly, Ofoto, etc.
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- Costco
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- Web
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- Online services
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- Shutterfly, Ofoto, etc.
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- Web pages (72 dpi)
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- Good for small files only! (72 dpi)
- Printing Tips
- Set the print size
- Set the correct printer and paper (including size, orientation, fit on paper)
- Your software gives you options, then your printer gives you options can be confusing
- Color management either let your software manage the colors, or let the printer do it, but not both!
- Set the color profile of the paper youre using
- Do a nozzle check beforehand. (Keep scrap plain paper around!)
- Clean the nozzles often.
- Use third-party inks and paper at your own peril!
- Email Tips
- If you dont have to, dont!
- Dont email big files! Anything ~1M or more is too big!
- Use software emailing features, or manually reduce the file size (72 dpi, 640 pixels is usually sufficient).
- Package up your images if you have many zip, etc.
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- Better yet use the Web!
- Attach the images avoid placing them in the body of your email (in-line).
- Web Tips
- If you have already enhanced your photos, make sure your service (Shutterfly, Ofoto, etc.) doesnt enhance them again!
- If you manage your own web pages, use small files (72 dpi)
- Software available to create galleries
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- Adobe Photoshop
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- CompuPic
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- ThumbsPlus
- Sharpening
- In digital terms, adding adjacent light and dark pixels to enhance contrast
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- Amount how much (gas pedal)
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- Halo (Radius) how many pixels affected
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- Threshold how many surrounding pixels considered edge
- Different needs
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- Print: inkjet, laser, offset, etc.
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- Web/email (screen)
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- After resizing
- Schools of thought
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- For output only
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- Workflow (artistic) sharpening
- Live Editing Session
- Parting Thoughts
- Good art comes of good craftspersonship.
- If It Moves You, Shoot It! Often!
- Practice! Practice! Practice!
- Recommended Reading
- Photography
- Blue Pixel Personal Photo Coach: Digital Photography Tips from the Trenches by David Schloss
- Perfect Exposure: Jim Zuckerman's Secrets to Great Photographs by Jim Zuckerman
- Designing a Photograph: Visual Techniques for Making Your Photographs Work by Bill Smith
- Examples: The Making of 40 Photographs by Ansel Adams
- Successful Underwater Photography by Brian Skerry, Howard Hall
- Adobe Photoshop
- Adobe Photoshop CS2 for Photographers by Martin Evening
- The Photoshop CS2 Book for Digital Photographers by Scott Kelby
- The Photoshop Elements 3 Book for Digital Photographers by Scott Kelby
- Photoshop Restoration & Retouching by Katrin Eismann
- Photoshop Masking & Compositing by Katrin Eismann
- The Photoshop Show Starring Russell Brown by Russell Brown
- Adobe Photoshop CS2 Classroom in a Book by Adobe Creative Team
- Adobe Photoshop Elements 3.0 Classroom in a Book by Adobe Creative Team
- Photoshop on the Web
- Adobe Photoshop ( http://www.adobe.com/products/ photoshop /overview.html )
- National Association of Photoshop Professionals (NAPP) ( http://www. photoshopuser .com/ )
- Photoshop News ( http:// photoshopnews .com/ )
- Photoshop Caf ( http://www. photoshopcafe .com/ )
- Adobe Evangelists ( http://www. adobeevangelists .com/ )
- Thank You For Coming! Now Go Take Pictures! Peter Liu Photography kaiscapes .com
- Supplemental Slides Begin Here
- Film Speed Trivia
- ASA A merican S tandards A ssociation. Most common film speed rating in the U.S. until the conversion to ISO. Only the name has changed.
- ISO I nternational S tandards O rganization. Most common film speed rating in the U.S. Doubling the value doubles the film speed.
- DIN D eutsche I ndustrie N orm . Based on a logarithmic scale where each increase represents 1/3 stop. E.g. ISO 800/30 on a roll of ISO (ASA) 800 film indicates that the DIN rating is 30.