Photomicrography Interactive Tutorials

• Color Temperature Conversion Calculator

  Learn how to determine the correct color conversion filter for balancing the color temperature of a microscope light source with the color temperature conversion calculator in this interactive java tutorial.

• Exposure and Color Balance

  Explore and discover how adjustments to exposure and color balance affect the quality of both ordinary photographs and photomicrographs in this interactive java tutorial featuring a variety of samples to choose from.

• Didymium Filters

  These color filters act to enhance certain tones and hues in color photomicrography. Use this tutorial to explore how didymium filters modify photomicrographs of specimens stained with eosin, fuchsin, and methylene blue.

• Filter Classes

  Filters are frequently utilized in optical microscopy, both for visualization of specimens and for photomicrography. Discover the visible light spectral characteristics of the major types of filters used in microscopy.

• Black Body Radiator Color Temperature

  Discover and observe how changing the temperature of a black body radiator affects the visible light spectrum and color temperature emitted by the radiator in this interactive tutorial.

• Color Temperature Nomograph

  Use the featured color temperature nomograph to calculate the filtration factor necessary to convert a light source from one color temperature to another in this interactive java tutorial.

• Photomask Reticle Operation

  Practice adjustment of the photomask reticle mounted in a focusing eyepiece using this interactive tutorial. The tutorial will initialize with both the image and the reticle out of focus, also giving a variety of specimen to choose from.

• Filters for Black and White Photomicrography

  Experiment and explore to determine the appropriate starting point for contrast control in Black and White Photomicrography using Kodak Wratten filters in this interactive java tutorial.

• Illuminated Reticles

  Microscopes equipped specifically for fluorescence illumination often have illuminated reticles in the eyepiece, which allow the microscopist to visualize faintly visible specimens superimposed against a very dark background.

• Exposure Metering

  Discover how the automatic camera metering system works to measure light intensity in the field of view and calculate exposure times based on light intensity in different parts of the specimen.

• Filter Control of Specimen Contrast in Black and White Photomicrography

  To enhance contrast, color filters are added to the microscope light path to absorb stained specimen color, rendering it either a darker or lighter shade of gray.

• Exposure Characteristic Curves and Image Contrast

  Explore the relationship between the slope of characteristic curves exhibited by transparency and negative films and the amount of contrast produced by these films.

• Exposure Calculation in Photomicrography

  Use a film exposure time measured from brackets under standardized conditions of magnification and numerical aperture to determine exposure for a new objective of different magnification and numerical aperture.

• Abbe Condenser Chromatic Aberrations

  Learn more as this featured interactive java tutorial demonstrates color fringes that occur at the field diaphragm edges as a result of chromatic aberration in Abbe condensers.

• Exposure Calculation (With ISO Correction) in Photomicrography

  Use a known film exposure time to determine exposure for a new objective of different magnification and numerical aperture using a film with a new ISO value.

Charge-Coupled Device (CCD) and Digital Electronics Tutorials

• Avalanche Diodes

  An avalanche photodiode is a silicon-based semiconductor containing a pn junction consisting of a positively doped p region and a negatively doped n region sandwiching an area of neutral charge termed the depletion region.

• Electron-Bombarded CCDs

  Electron-bombarded charge-coupled devices (CCDs) are a relatively new development in which photons are detected by a photocathode in a manner similar to an image intensifier.

• CCD Pixel Binning

  Discover how clock signals controlling a CCD can be used to combine integrated charge from adjacent pixels to improve signal-to-noise ratios and increase the readout frame rate.

• CCD Blooming

  Under conditions where a CCD is exposed to high intensity illumination, it is possible to exhaust the storage capacity of the CCD wells, a condition known as blooming. Examine the operation of a lateral overflow drain to prevent blooming.

• CCD Clocking Schemes

  Charge transfer through CCD shift registers occurs after integration to relocate accumulated charge information to the sense amplifier, which is physically separated from the parallel pixel array.

• Building A Charge-Coupled Device

  Explore the steps utilized in the construction of a charge-coupled device (CCD) as a portion of an individual pixel gate is fabricated on a silicon wafer simultaneously with thousands or even millions of neighboring elements.

• Building A Charge-Coupled Device (Version 2)

  Like the first version this tutorial examines the fabrication of a CCD as a portion of an individual pixel gate is fabricated on a silicon wafer simultaneously with thousands or even millions of neighboring elements.

• Electronic Shutters

  Electronic shutters are employed in charge-coupled devices (CCDs) to control integration time (exposure) of the photodiode array and reduce smear when capturing moving objects in the microscope.

• CCD Operation

  Explore the operation of a charge-coupled device imaging semiconductor as modern CCDs consist of a light-sensitive sandwich of insulating silicon dioxide, an array of photodiodes, and metal electrodes.

• Frame-Transfer CCD Operation

  Designed to operate fast without a shutter or synchronized strobe, frame-transfer CCDs exhibit higher frame rates than full-frame designs. Explore image acquisition and transfer in frame-transfer charge-coupled devices.

• Interaction of Photons with Silicon

  In a charge-coupled device (CCD) incident light must first pass through a silicon nitride passivation coating as well as several thin films of silicon dioxide and polysilicon gate structures before being absorbed into the silicon substrate.

• Full-Frame CCD Operation

  Full-frame charge-coupled devices have the simplest architecture and are the easiest built and operated. They feature high-density pixel arrays capable of producing images with the highest resolution available.

• Interline CCD Operation

  Interline charge-coupled device architecture is designed to compensate for many of the shortcomings of frame-transfer CCDs. Composed of a hybrid structure incorporating a separate photodiode and a CCD storage region.

• Microlens Arrays

  Microlens arrays (also referred to as microlenticular arrays or lenslet arrays) are used to increase the optical fill factor in CCDs, such as interline devices, that suffer from reduced aperture due to metal shielding.

• Photomultiplier Tubes

  Photomultiplier tubes, useful for light detection of very weak signals, are photoemissive devices in which the absorption of a photon results in the emission of an electron. Learn more in this interactive tutorial.

• End-On Photomultipliers

  Photomultiplier tubes, useful for light detection of very weak signals, are photoemissive devices in which the absorption of a photon results in the emission of an electron as explained in this tutorial.

• Proximity-Focused Image Intensifiers

  Learn more about image intensifiers as they were developed for military use to enhance our night vision and are often referred to as wafer tubes or proximity-focused intensifiers.

Modulation Transfer Function

• Diffraction Effects on Image Contrast

  The featured tutorial utilizes a periodic line grating as the specimen and simulates images produced with a diffraction-limited optical microscope as a function of spatial frequency.

• Cutoff Frequency and Airy Disk Size

  Explore the changes in the point spread function distribution as spatial frequency cutoff is varied in a typical modulation transfer function plot in this featured interactive java tutorial.

• Numerical Aperture Effects on MTF

  Examine the effect of microscope objective and condenser numerical aperture size on the relative modulation as a function of specimen spatial frequency in this interactive java tutorial.

• Test Target Intensity Scans

  The interactive java tutorial demonstrates intensity scans made from images of the periodic lines present on the MBL-NNF test target measured with a plan apochromatic objective.

• Periodic Diffraction Images

  Discover and learn more about diffraction images being produced by a periodic object at several focal depths creating a three-dimensional diffraction pattern that is periodic both along the optical axis and laterally.

• Contrast Enhancement Technique MTF Curves

  Explore the effects of popular contrast modes on image contrast and the modulation transfer function of the modified microscope in this interactive java tutorial.